Rollup merge of #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 #106311

r? cjgillot
This commit is contained in:
Matthias Krüger 2023-01-26 15:02:20 +01:00 committed by GitHub
commit 70a665a005
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3 changed files with 190 additions and 178 deletions

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@ -43,6 +43,7 @@
#![feature(min_specialization)]
#![feature(trusted_len)]
#![feature(type_alias_impl_trait)]
#![feature(strict_provenance)]
#![feature(associated_type_bounds)]
#![feature(rustc_attrs)]
#![feature(control_flow_enum)]

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@ -2,6 +2,8 @@
#![allow(rustc::usage_of_ty_tykind)]
pub mod tls;
use crate::arena::Arena;
use crate::dep_graph::{DepGraph, DepKindStruct};
use crate::infer::canonical::{CanonicalVarInfo, CanonicalVarInfos};
@ -1212,178 +1214,6 @@ CloneLiftImpls! { for<'tcx> {
Constness, traits::WellFormedLoc, ImplPolarity, crate::mir::ReturnConstraint,
} }
pub mod tls {
use super::{ptr_eq, GlobalCtxt, TyCtxt};
use crate::dep_graph::TaskDepsRef;
use crate::ty::query;
use rustc_data_structures::sync::{self, Lock};
use rustc_errors::Diagnostic;
use std::mem;
use thin_vec::ThinVec;
#[cfg(not(parallel_compiler))]
use std::cell::Cell;
#[cfg(parallel_compiler)]
use rustc_rayon_core as rayon_core;
/// 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>,
/// 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>,
/// 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>>>,
/// Used to prevent queries from calling too deeply.
pub query_depth: usize,
/// The current dep graph task. This is used to add dependencies to queries
/// when executing them.
pub task_deps: TaskDepsRef<'a>,
}
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,
}
}
}
/// 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`.
#[cfg(parallel_compiler)]
#[inline]
fn set_tlv<F: FnOnce() -> R, R>(value: usize, f: F) -> R {
rayon_core::tlv::with(value, f)
}
/// Gets Rayon's thread-local variable, which is preserved for Rayon jobs.
/// This is used to get the pointer to the current `ImplicitCtxt`.
#[cfg(parallel_compiler)]
#[inline]
pub fn get_tlv() -> usize {
rayon_core::tlv::get()
}
#[cfg(not(parallel_compiler))]
thread_local! {
/// A thread local variable that stores a pointer to the current `ImplicitCtxt`.
static TLV: Cell<usize> = const { Cell::new(0) };
}
/// 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`.
#[cfg(not(parallel_compiler))]
#[inline]
fn set_tlv<F: FnOnce() -> R, R>(value: usize, 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()
}
/// Gets the pointer to the current `ImplicitCtxt`.
#[cfg(not(parallel_compiler))]
#[inline]
fn get_tlv() -> usize {
TLV.with(|tlv| tlv.get())
}
/// 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,
{
set_tlv(context as *const _ as usize, || f(&context))
}
/// 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 = get_tlv();
if context == 0 {
f(None)
} else {
// We could get an `ImplicitCtxt` pointer from another thread.
// Ensure that `ImplicitCtxt` is `Sync`.
sync::assert_sync::<ImplicitCtxt<'_, '_>>();
unsafe { f(Some(&*(context as *const ImplicitCtxt<'_, '_>))) }
}
}
/// 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")))
}
/// 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| unsafe {
assert!(ptr_eq(context.tcx.gcx, tcx.gcx));
let context: &ImplicitCtxt<'_, '_> = mem::transmute(context);
f(context)
})
}
/// 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))
}
/// 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)))
}
}
macro_rules! sty_debug_print {
($fmt: expr, $ctxt: expr, $($variant: ident),*) => {{
// Curious inner module to allow variant names to be used as
@ -2416,12 +2246,6 @@ pub struct DeducedParamAttrs {
pub read_only: bool,
}
// We are comparing types with different invariant lifetimes, so `ptr::eq`
// won't work for us.
fn ptr_eq<T, U>(t: *const T, u: *const U) -> bool {
t as *const () == u as *const ()
}
pub fn provide(providers: &mut ty::query::Providers) {
providers.module_reexports =
|tcx, id| tcx.resolutions(()).reexport_map.get(&id).map(|v| &v[..]);

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@ -0,0 +1,187 @@
use super::{GlobalCtxt, TyCtxt};
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;
/// 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>,
/// 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>,
/// 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>>>,
/// Used to prevent queries from calling too deeply.
pub query_depth: usize,
/// The current dep graph task. This is used to add dependencies to queries
/// when executing them.
pub task_deps: TaskDepsRef<'a>,
}
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,
}
}
}
#[cfg(parallel_compiler)]
mod tlv {
use rustc_rayon_core as rayon_core;
use std::ptr;
/// 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())
}
/// 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)
}
}
#[cfg(not(parallel_compiler))]
mod tlv {
use std::cell::Cell;
use std::ptr;
thread_local! {
/// A thread local variable that stores a pointer to the current `ImplicitCtxt`.
static TLV: Cell<*const ()> = const { Cell::new(ptr::null()) };
}
/// Gets the pointer to the current `ImplicitCtxt`.
#[inline]
pub(super) fn get_tlv() -> *const () {
TLV.with(|tlv| tlv.get())
}
/// 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()
}
}
#[inline]
fn erase(context: &ImplicitCtxt<'_, '_>) -> *const () {
context as *const _ as *const ()
}
#[inline]
unsafe fn downcast<'a, 'tcx>(context: *const ()) -> &'a ImplicitCtxt<'a, 'tcx> {
&*(context as *const ImplicitCtxt<'a, 'tcx>)
}
/// 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))
}
/// 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<'_, '_>>();
unsafe { f(Some(downcast(context))) }
}
}
/// 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")))
}
/// 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 ()
));
let context: &ImplicitCtxt<'_, '_> = unsafe { mem::transmute(context) };
f(context)
})
}
/// 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))
}
/// 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)))
}