rustc_interface/
callbacks.rs

1//! Throughout the compiler tree, there are several places which want to have
2//! access to state or queries while being inside crates that are dependencies
3//! of `rustc_middle`. To facilitate this, we have the
4//! `rustc_data_structures::AtomicRef` type, which allows us to setup a global
5//! static which can then be set in this file at program startup.
6//!
7//! See `SPAN_TRACK` for an example of how to set things up.
8//!
9//! The functions in this file should fall back to the default set in their
10//! origin crate when the `TyCtxt` is not present in TLS.
11
12use std::fmt;
13
14use rustc_errors::{DiagInner, TRACK_DIAGNOSTIC};
15use rustc_middle::dep_graph::{DepNodeExt, TaskDepsRef};
16use rustc_middle::ty::tls;
17use rustc_query_impl::QueryCtxt;
18use rustc_query_system::dep_graph::dep_node::default_dep_kind_debug;
19use rustc_query_system::dep_graph::{DepContext, DepKind, DepNode};
20
21fn track_span_parent(def_id: rustc_span::def_id::LocalDefId) {
22    tls::with_context_opt(|icx| {
23        if let Some(icx) = icx {
24            // `track_span_parent` gets called a lot from HIR lowering code.
25            // Skip doing anything if we aren't tracking dependencies.
26            let tracks_deps = match icx.task_deps {
27                TaskDepsRef::Allow(..) => true,
28                TaskDepsRef::EvalAlways | TaskDepsRef::Ignore | TaskDepsRef::Forbid => false,
29            };
30            if tracks_deps {
31                let _span = icx.tcx.source_span(def_id);
32                // Sanity check: relative span's parent must be an absolute span.
33                debug_assert_eq!(_span.data_untracked().parent, None);
34            }
35        }
36    })
37}
38
39/// This is a callback from `rustc_errors` as it cannot access the implicit state
40/// in `rustc_middle` otherwise. It is used when diagnostic messages are
41/// emitted and stores them in the current query, if there is one.
42fn track_diagnostic<R>(diagnostic: DiagInner, f: &mut dyn FnMut(DiagInner) -> R) -> R {
43    tls::with_context_opt(|icx| {
44        if let Some(icx) = icx {
45            icx.tcx.dep_graph.record_diagnostic(QueryCtxt::new(icx.tcx), &diagnostic);
46
47            // Diagnostics are tracked, we can ignore the dependency.
48            let icx = tls::ImplicitCtxt { task_deps: TaskDepsRef::Ignore, ..icx.clone() };
49            tls::enter_context(&icx, move || (*f)(diagnostic))
50        } else {
51            // In any other case, invoke diagnostics anyway.
52            (*f)(diagnostic)
53        }
54    })
55}
56
57/// This is a callback from `rustc_hir` as it cannot access the implicit state
58/// in `rustc_middle` otherwise.
59fn def_id_debug(def_id: rustc_hir::def_id::DefId, f: &mut fmt::Formatter<'_>) -> fmt::Result {
60    write!(f, "DefId({}:{}", def_id.krate, def_id.index.index())?;
61    tls::with_opt(|opt_tcx| {
62        if let Some(tcx) = opt_tcx {
63            write!(f, " ~ {}", tcx.def_path_debug_str(def_id))?;
64        }
65        Ok(())
66    })?;
67    write!(f, ")")
68}
69
70/// This is a callback from `rustc_query_system` as it cannot access the implicit state
71/// in `rustc_middle` otherwise.
72pub fn dep_kind_debug(kind: DepKind, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
73    tls::with_opt(|opt_tcx| {
74        if let Some(tcx) = opt_tcx {
75            write!(f, "{}", tcx.dep_kind_info(kind).name)
76        } else {
77            default_dep_kind_debug(kind, f)
78        }
79    })
80}
81
82/// This is a callback from `rustc_query_system` as it cannot access the implicit state
83/// in `rustc_middle` otherwise.
84pub fn dep_node_debug(node: DepNode, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
85    write!(f, "{:?}(", node.kind)?;
86
87    tls::with_opt(|opt_tcx| {
88        if let Some(tcx) = opt_tcx {
89            if let Some(def_id) = node.extract_def_id(tcx) {
90                write!(f, "{}", tcx.def_path_debug_str(def_id))?;
91            } else if let Some(ref s) = tcx.dep_graph.dep_node_debug_str(node) {
92                write!(f, "{s}")?;
93            } else {
94                write!(f, "{}", node.hash)?;
95            }
96        } else {
97            write!(f, "{}", node.hash)?;
98        }
99        Ok(())
100    })?;
101
102    write!(f, ")")
103}
104
105/// Sets up the callbacks in prior crates which we want to refer to the
106/// TyCtxt in.
107pub fn setup_callbacks() {
108    rustc_span::SPAN_TRACK.swap(&(track_span_parent as fn(_)));
109    rustc_hir::def_id::DEF_ID_DEBUG.swap(&(def_id_debug as fn(_, &mut fmt::Formatter<'_>) -> _));
110    rustc_query_system::dep_graph::dep_node::DEP_KIND_DEBUG
111        .swap(&(dep_kind_debug as fn(_, &mut fmt::Formatter<'_>) -> _));
112    rustc_query_system::dep_graph::dep_node::DEP_NODE_DEBUG
113        .swap(&(dep_node_debug as fn(_, &mut fmt::Formatter<'_>) -> _));
114    TRACK_DIAGNOSTIC.swap(&(track_diagnostic as _));
115}
rustc_interface/callbacks.rs

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rustc_interface/
callbacks.rs
