rustc_middle/ty/context/
tls.rs

1use rustc_data_structures::sync;
2
3use super::{GlobalCtxt, TyCtxt};
4use crate::dep_graph::TaskDepsRef;
5use crate::query::QueryJobId;
6
7/// This is the implicit state of rustc. It contains the current
8/// `TyCtxt` and query. It is updated when creating a local interner or
9/// executing a new query. Whenever there's a `TyCtxt` value available
10/// you should also have access to an `ImplicitCtxt` through the functions
11/// in this module.
12pub struct ImplicitCtxt<'a, 'tcx> {
13    /// The current `TyCtxt`.
14    pub tcx: TyCtxt<'tcx>,
15
16    /// The current query job, if any.
17    pub query: Option<QueryJobId>,
18
19    /// Used to prevent queries from calling too deeply.
20    pub query_depth: usize,
21
22    /// The current dep graph task. This is used to add dependencies to queries
23    /// when executing them.
24    pub task_deps: TaskDepsRef<'a>,
25}
26
27impl<'a, 'tcx> ImplicitCtxt<'a, 'tcx> {
28    pub fn new(gcx: &'tcx GlobalCtxt<'tcx>) -> Self {
29        let tcx = TyCtxt { gcx };
30        ImplicitCtxt { tcx, query: None, query_depth: 0, task_deps: TaskDepsRef::Ignore }
31    }
32}
33
34// Import the thread-local variable from Rayon, which is preserved for Rayon jobs.
35use rustc_thread_pool::tlv::TLV;
36
37#[inline]
38fn erase(context: &ImplicitCtxt<'_, '_>) -> *const () {
39    context as *const _ as *const ()
40}
41
42#[inline]
43unsafe fn downcast<'a, 'tcx>(context: *const ()) -> &'a ImplicitCtxt<'a, 'tcx> {
44    unsafe { &*(context as *const ImplicitCtxt<'a, 'tcx>) }
45}
46
47/// Sets `context` as the new current `ImplicitCtxt` for the duration of the function `f`.
48#[inline]
49pub fn enter_context<'a, 'tcx, F, R>(context: &ImplicitCtxt<'a, 'tcx>, f: F) -> R
50where
51    F: FnOnce() -> R,
52{
53    TLV.with(|tlv| {
54        let old = tlv.replace(erase(context));
55        let _reset = rustc_data_structures::defer(move || tlv.set(old));
56        f()
57    })
58}
59
60/// Allows access to the current `ImplicitCtxt` in a closure if one is available.
61#[inline]
62#[track_caller]
63pub fn with_context_opt<F, R>(f: F) -> R
64where
65    F: for<'a, 'tcx> FnOnce(Option<&ImplicitCtxt<'a, 'tcx>>) -> R,
66{
67    let context = TLV.get();
68    if context.is_null() {
69        f(None)
70    } else {
71        // We could get an `ImplicitCtxt` pointer from another thread.
72        // Ensure that `ImplicitCtxt` is `DynSync`.
73        sync::assert_dyn_sync::<ImplicitCtxt<'_, '_>>();
74
75        unsafe { f(Some(downcast(context))) }
76    }
77}
78
79/// Allows access to the current `ImplicitCtxt`.
80/// Panics if there is no `ImplicitCtxt` available.
81#[inline]
82pub fn with_context<F, R>(f: F) -> R
83where
84    F: for<'a, 'tcx> FnOnce(&ImplicitCtxt<'a, 'tcx>) -> R,
85{
86    with_context_opt(|opt_context| f(opt_context.expect("no ImplicitCtxt stored in tls")))
87}
88
89/// Allows access to the `TyCtxt` in the current `ImplicitCtxt`.
90/// Panics if there is no `ImplicitCtxt` available.
91#[inline]
92pub fn with<F, R>(f: F) -> R
93where
94    F: for<'tcx> FnOnce(TyCtxt<'tcx>) -> R,
95{
96    with_context(|context| f(context.tcx))
97}
98
99/// Allows access to the `TyCtxt` in the current `ImplicitCtxt`.
100/// The closure is passed None if there is no `ImplicitCtxt` available.
101#[inline]
102#[track_caller]
103pub fn with_opt<F, R>(f: F) -> R
104where
105    F: for<'tcx> FnOnce(Option<TyCtxt<'tcx>>) -> R,
106{
107    with_context_opt(
108        #[track_caller]
109        |opt_context| f(opt_context.map(|context| context.tcx)),
110    )
111}
rustc_middle/ty/context/tls.rs

rustc_middle/ty/context/
tls.rs
