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Rollup merge of rust-lang#107150 - Nilstrieb:thread-local-cleanups, r…
…=cjgillot `ty::tls` cleanups Pull it out into a separate file, make the conditional compilation more obvious and give the internal functions better names. Pulled out of rust-lang#106311 r? cjgillot
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,187 @@ | ||
| use super::{GlobalCtxt, TyCtxt}; | ||
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| use crate::dep_graph::TaskDepsRef; | ||
| use crate::ty::query; | ||
| use rustc_data_structures::sync::{self, Lock}; | ||
| use rustc_errors::Diagnostic; | ||
| use std::mem; | ||
| use std::ptr; | ||
| use thin_vec::ThinVec; | ||
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| /// This is the implicit state of rustc. It contains the current | ||
| /// `TyCtxt` and query. It is updated when creating a local interner or | ||
| /// executing a new query. Whenever there's a `TyCtxt` value available | ||
| /// you should also have access to an `ImplicitCtxt` through the functions | ||
| /// in this module. | ||
| #[derive(Clone)] | ||
| pub struct ImplicitCtxt<'a, 'tcx> { | ||
| /// The current `TyCtxt`. | ||
| pub tcx: TyCtxt<'tcx>, | ||
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| /// The current query job, if any. This is updated by `JobOwner::start` in | ||
| /// `ty::query::plumbing` when executing a query. | ||
| pub query: Option<query::QueryJobId>, | ||
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| /// Where to store diagnostics for the current query job, if any. | ||
| /// This is updated by `JobOwner::start` in `ty::query::plumbing` when executing a query. | ||
| pub diagnostics: Option<&'a Lock<ThinVec<Diagnostic>>>, | ||
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| /// Used to prevent queries from calling too deeply. | ||
| pub query_depth: usize, | ||
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| /// The current dep graph task. This is used to add dependencies to queries | ||
| /// when executing them. | ||
| pub task_deps: TaskDepsRef<'a>, | ||
| } | ||
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| impl<'a, 'tcx> ImplicitCtxt<'a, 'tcx> { | ||
| pub fn new(gcx: &'tcx GlobalCtxt<'tcx>) -> Self { | ||
| let tcx = TyCtxt { gcx }; | ||
| ImplicitCtxt { | ||
| tcx, | ||
| query: None, | ||
| diagnostics: None, | ||
| query_depth: 0, | ||
| task_deps: TaskDepsRef::Ignore, | ||
| } | ||
| } | ||
| } | ||
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| #[cfg(parallel_compiler)] | ||
| mod tlv { | ||
| use rustc_rayon_core as rayon_core; | ||
| use std::ptr; | ||
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| /// Gets Rayon's thread-local variable, which is preserved for Rayon jobs. | ||
| /// This is used to get the pointer to the current `ImplicitCtxt`. | ||
| #[inline] | ||
| pub(super) fn get_tlv() -> *const () { | ||
| ptr::from_exposed_addr(rayon_core::tlv::get()) | ||
| } | ||
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| /// Sets Rayon's thread-local variable, which is preserved for Rayon jobs | ||
| /// to `value` during the call to `f`. It is restored to its previous value after. | ||
| /// This is used to set the pointer to the new `ImplicitCtxt`. | ||
| #[inline] | ||
| pub(super) fn with_tlv<F: FnOnce() -> R, R>(value: *const (), f: F) -> R { | ||
| rayon_core::tlv::with(value.expose_addr(), f) | ||
| } | ||
| } | ||
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| #[cfg(not(parallel_compiler))] | ||
| mod tlv { | ||
| use std::cell::Cell; | ||
| use std::ptr; | ||
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| thread_local! { | ||
| /// A thread local variable that stores a pointer to the current `ImplicitCtxt`. | ||
| static TLV: Cell<*const ()> = const { Cell::new(ptr::null()) }; | ||
| } | ||
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| /// Gets the pointer to the current `ImplicitCtxt`. | ||
| #[inline] | ||
| pub(super) fn get_tlv() -> *const () { | ||
| TLV.with(|tlv| tlv.get()) | ||
| } | ||
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| /// Sets TLV to `value` during the call to `f`. | ||
| /// It is restored to its previous value after. | ||
| /// This is used to set the pointer to the new `ImplicitCtxt`. | ||
| #[inline] | ||
| pub(super) fn with_tlv<F: FnOnce() -> R, R>(value: *const (), f: F) -> R { | ||
| let old = get_tlv(); | ||
| let _reset = rustc_data_structures::OnDrop(move || TLV.with(|tlv| tlv.set(old))); | ||
| TLV.with(|tlv| tlv.set(value)); | ||
| f() | ||
| } | ||
| } | ||
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| #[inline] | ||
| fn erase(context: &ImplicitCtxt<'_, '_>) -> *const () { | ||
| context as *const _ as *const () | ||
| } | ||
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| #[inline] | ||
| unsafe fn downcast<'a, 'tcx>(context: *const ()) -> &'a ImplicitCtxt<'a, 'tcx> { | ||
| &*(context as *const ImplicitCtxt<'a, 'tcx>) | ||
| } | ||
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| /// Sets `context` as the new current `ImplicitCtxt` for the duration of the function `f`. | ||
| #[inline] | ||
| pub fn enter_context<'a, 'tcx, F, R>(context: &ImplicitCtxt<'a, 'tcx>, f: F) -> R | ||
| where | ||
| F: FnOnce(&ImplicitCtxt<'a, 'tcx>) -> R, | ||
| { | ||
| tlv::with_tlv(erase(context), || f(&context)) | ||
| } | ||
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| /// Allows access to the current `ImplicitCtxt` in a closure if one is available. | ||
| #[inline] | ||
| pub fn with_context_opt<F, R>(f: F) -> R | ||
| where | ||
| F: for<'a, 'tcx> FnOnce(Option<&ImplicitCtxt<'a, 'tcx>>) -> R, | ||
| { | ||
| let context = tlv::get_tlv(); | ||
| if context.is_null() { | ||
| f(None) | ||
| } else { | ||
| // We could get an `ImplicitCtxt` pointer from another thread. | ||
| // Ensure that `ImplicitCtxt` is `Sync`. | ||
| sync::assert_sync::<ImplicitCtxt<'_, '_>>(); | ||
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| unsafe { f(Some(downcast(context))) } | ||
| } | ||
| } | ||
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| /// Allows access to the current `ImplicitCtxt`. | ||
| /// Panics if there is no `ImplicitCtxt` available. | ||
| #[inline] | ||
| pub fn with_context<F, R>(f: F) -> R | ||
| where | ||
| F: for<'a, 'tcx> FnOnce(&ImplicitCtxt<'a, 'tcx>) -> R, | ||
| { | ||
| with_context_opt(|opt_context| f(opt_context.expect("no ImplicitCtxt stored in tls"))) | ||
| } | ||
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| /// Allows access to the current `ImplicitCtxt` whose tcx field is the same as the tcx argument | ||
| /// passed in. This means the closure is given an `ImplicitCtxt` with the same `'tcx` lifetime | ||
| /// as the `TyCtxt` passed in. | ||
| /// This will panic if you pass it a `TyCtxt` which is different from the current | ||
| /// `ImplicitCtxt`'s `tcx` field. | ||
| #[inline] | ||
| pub fn with_related_context<'tcx, F, R>(tcx: TyCtxt<'tcx>, f: F) -> R | ||
| where | ||
| F: FnOnce(&ImplicitCtxt<'_, 'tcx>) -> R, | ||
| { | ||
| with_context(|context| { | ||
| // The two gcx have different invariant lifetimes, so we need to erase them for the comparison. | ||
| assert!(ptr::eq( | ||
| context.tcx.gcx as *const _ as *const (), | ||
| tcx.gcx as *const _ as *const () | ||
| )); | ||
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| let context: &ImplicitCtxt<'_, '_> = unsafe { mem::transmute(context) }; | ||
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| f(context) | ||
| }) | ||
| } | ||
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| /// Allows access to the `TyCtxt` in the current `ImplicitCtxt`. | ||
| /// Panics if there is no `ImplicitCtxt` available. | ||
| #[inline] | ||
| pub fn with<F, R>(f: F) -> R | ||
| where | ||
| F: for<'tcx> FnOnce(TyCtxt<'tcx>) -> R, | ||
| { | ||
| with_context(|context| f(context.tcx)) | ||
| } | ||
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| /// Allows access to the `TyCtxt` in the current `ImplicitCtxt`. | ||
| /// The closure is passed None if there is no `ImplicitCtxt` available. | ||
| #[inline] | ||
| pub fn with_opt<F, R>(f: F) -> R | ||
| where | ||
| F: for<'tcx> FnOnce(Option<TyCtxt<'tcx>>) -> R, | ||
| { | ||
| with_context_opt(|opt_context| f(opt_context.map(|context| context.tcx))) | ||
| } |