From ed78d930a95ad388a0b782c1e9e3a8f78ac6aa9c Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?John=20K=C3=A5re=20Alsaker?= Date: Wed, 5 Dec 2018 16:51:58 +0100 Subject: [PATCH] Replace LockCell with atomic types --- src/librustc/lib.rs | 1 + src/librustc/session/mod.rs | 45 ++++-- src/librustc_data_structures/lib.rs | 23 +++ src/librustc_data_structures/sync.rs | 210 ++++++++------------------- src/librustc_driver/lib.rs | 5 +- src/librustc_errors/lib.rs | 14 +- 6 files changed, 123 insertions(+), 175 deletions(-) diff --git a/src/librustc/lib.rs b/src/librustc/lib.rs index ddb0c5bf22ab6..4f3349e65d0f5 100644 --- a/src/librustc/lib.rs +++ b/src/librustc/lib.rs @@ -64,6 +64,7 @@ #![feature(trusted_len)] #![feature(vec_remove_item)] #![feature(step_trait)] +#![feature(stmt_expr_attributes)] #![feature(integer_atomics)] #![feature(test)] #![feature(in_band_lifetimes)] diff --git a/src/librustc/session/mod.rs b/src/librustc/session/mod.rs index 293cd0c7c546d..365eaad1764a2 100644 --- a/src/librustc/session/mod.rs +++ b/src/librustc/session/mod.rs @@ -26,7 +26,10 @@ use util::common::{duration_to_secs_str, ErrorReported}; use util::common::ProfileQueriesMsg; use rustc_data_structures::base_n; -use rustc_data_structures::sync::{self, Lrc, Lock, LockCell, OneThread, Once, RwLock}; +use rustc_data_structures::sync::{ + self, Lrc, Lock, OneThread, Once, RwLock, AtomicU64, AtomicUsize, AtomicBool, Ordering, + Ordering::SeqCst, +}; use errors::{self, DiagnosticBuilder, DiagnosticId, Applicability}; use errors::emitter::{Emitter, EmitterWriter}; @@ -51,7 +54,6 @@ use std::io::Write; use std::path::{Path, PathBuf}; use std::time::Duration; use std::sync::mpsc; -use std::sync::atomic::{AtomicUsize, Ordering}; mod code_stats; pub mod config; @@ -142,15 +144,15 @@ pub struct Session { /// If -zfuel=crate=n is specified, Some(crate). optimization_fuel_crate: Option, /// If -zfuel=crate=n is specified, initially set to n. Otherwise 0. - optimization_fuel_limit: LockCell, + optimization_fuel_limit: AtomicU64, /// We're rejecting all further optimizations. - out_of_fuel: LockCell, + out_of_fuel: AtomicBool, // The next two are public because the driver needs to read them. /// If -zprint-fuel=crate, Some(crate). pub print_fuel_crate: Option, /// Always set to zero and incremented so that we can print fuel expended by a crate. - pub print_fuel: LockCell, + pub print_fuel: AtomicU64, /// Loaded up early on in the initialization of this `Session` to avoid /// false positives about a job server in our environment. @@ -859,32 +861,43 @@ impl Session { self.perf_stats.normalize_projection_ty.load(Ordering::Relaxed)); } - /// We want to know if we're allowed to do an optimization for crate foo from -z fuel=foo=n. - /// This expends fuel if applicable, and records fuel if applicable. - pub fn consider_optimizing String>(&self, crate_name: &str, msg: T) -> bool { + #[inline(never)] + #[cold] + pub fn consider_optimizing_cold String>(&self, crate_name: &str, msg: T) -> bool { let mut ret = true; if let Some(ref c) = self.optimization_fuel_crate { if c == crate_name { assert_eq!(self.query_threads(), 1); - let fuel = self.optimization_fuel_limit.get(); + let fuel = self.optimization_fuel_limit.load(SeqCst); ret = fuel != 0; - if fuel == 0 && !self.out_of_fuel.get() { + if fuel == 0 && !self.out_of_fuel.load(SeqCst) { eprintln!("optimization-fuel-exhausted: {}", msg()); - self.out_of_fuel.set(true); + self.out_of_fuel.store(true, SeqCst); } else if fuel > 0 { - self.optimization_fuel_limit.set(fuel - 1); + self.optimization_fuel_limit.store(fuel - 1, SeqCst); } } } if let Some(ref c) = self.print_fuel_crate { if c == crate_name { assert_eq!(self.query_threads(), 1); - self.print_fuel.set(self.print_fuel.get() + 1); + self.print_fuel.store(self.print_fuel.load(SeqCst) + 1, SeqCst); } } ret } + /// We want to know if we're allowed to do an optimization for crate foo from -z fuel=foo=n. + /// This expends fuel if applicable, and records fuel if applicable. + #[inline(always)] + pub fn consider_optimizing String>(&self, crate_name: &str, msg: T) -> bool { + if likely!(self.optimization_fuel_crate.is_none() && self.print_fuel_crate.is_none()) { + true + } else { + self.consider_optimizing_cold(crate_name, msg) + } + } + /// Returns the number of query threads that should be used for this /// compilation pub fn query_threads_from_opts(opts: &config::Options) -> usize { @@ -1121,9 +1134,9 @@ pub fn build_session_( let optimization_fuel_crate = sopts.debugging_opts.fuel.as_ref().map(|i| i.0.clone()); let optimization_fuel_limit = - LockCell::new(sopts.debugging_opts.fuel.as_ref().map(|i| i.1).unwrap_or(0)); + AtomicU64::new(sopts.debugging_opts.fuel.as_ref().map(|i| i.1).unwrap_or(0)); let print_fuel_crate = sopts.debugging_opts.print_fuel.clone(); - let print_fuel = LockCell::new(0); + let print_fuel = AtomicU64::new(0); let working_dir = env::current_dir().unwrap_or_else(|e| p_s.span_diagnostic @@ -1182,7 +1195,7 @@ pub fn build_session_( optimization_fuel_limit, print_fuel_crate, print_fuel, - out_of_fuel: LockCell::new(false), + out_of_fuel: AtomicBool::new(false), // Note that this is unsafe because it may misinterpret file descriptors // on Unix as jobserver file descriptors. We hopefully execute this near // the beginning of the process though to ensure we don't get false diff --git a/src/librustc_data_structures/lib.rs b/src/librustc_data_structures/lib.rs index 8e0ecb70c6896..9c5760dc050ca 100644 --- a/src/librustc_data_structures/lib.rs +++ b/src/librustc_data_structures/lib.rs @@ -30,6 +30,9 @@ #![feature(allow_internal_unstable)] #![feature(vec_resize_with)] #![feature(hash_raw_entry)] +#![feature(stmt_expr_attributes)] +#![feature(core_intrinsics)] +#![feature(integer_atomics)] #![cfg_attr(unix, feature(libc))] #![cfg_attr(test, feature(test))] @@ -58,6 +61,26 @@ extern crate rustc_cratesio_shim; pub use rustc_serialize::hex::ToHex; +#[macro_export] +macro_rules! likely { + ($e:expr) => { + #[allow(unused_unsafe)] + { + unsafe { std::intrinsics::likely($e) } + } + } +} + +#[macro_export] +macro_rules! unlikely { + ($e:expr) => { + #[allow(unused_unsafe)] + { + unsafe { std::intrinsics::unlikely($e) } + } + } +} + pub mod macros; pub mod svh; pub mod base_n; diff --git a/src/librustc_data_structures/sync.rs b/src/librustc_data_structures/sync.rs index 6a4012c81984d..d1c898cba6b85 100644 --- a/src/librustc_data_structures/sync.rs +++ b/src/librustc_data_structures/sync.rs @@ -20,10 +20,6 @@ //! It internally uses `parking_lot::RwLock` if cfg!(parallel_queries) is true, //! `RefCell` otherwise. //! -//! `LockCell` is a thread safe version of `Cell`, with `set` and `get` operations. -//! It can never deadlock. It uses `Cell` when -//! cfg!(parallel_queries) is false, otherwise it is a `Lock`. -//! //! `MTLock` is a mutex which disappears if cfg!(parallel_queries) is false. //! //! `MTRef` is a immutable reference if cfg!(parallel_queries), and an mutable reference otherwise. @@ -33,11 +29,7 @@ use std::collections::HashMap; use std::hash::{Hash, BuildHasher}; -use std::cmp::Ordering; use std::marker::PhantomData; -use std::fmt::Debug; -use std::fmt::Formatter; -use std::fmt; use std::ops::{Deref, DerefMut}; use owning_ref::{Erased, OwningRef}; @@ -64,6 +56,9 @@ pub fn serial_scope(f: F) -> R f(&SerialScope) } +pub use std::sync::atomic::Ordering::SeqCst; +pub use std::sync::atomic::Ordering; + cfg_if! { if #[cfg(not(parallel_queries))] { pub auto trait Send {} @@ -79,6 +74,62 @@ cfg_if! { } } + use std::ops::Add; + + #[derive(Debug)] + pub struct Atomic(Cell); + + impl Atomic { + pub fn new(v: T) -> Self { + Atomic(Cell::new(v)) + } + } + + impl Atomic { + pub fn into_inner(self) -> T { + self.0.into_inner() + } + + pub fn load(&self, _: Ordering) -> T { + self.0.get() + } + + pub fn store(&self, val: T, _: Ordering) { + self.0.set(val) + } + + pub fn swap(&self, val: T, _: Ordering) -> T { + self.0.replace(val) + } + + pub fn compare_exchange(&self, + current: T, + new: T, + _: Ordering, + _: Ordering) + -> Result { + let read = self.0.get(); + if read == current { + self.0.set(new); + Ok(read) + } else { + Err(read) + } + } + } + + impl + Copy> Atomic { + pub fn fetch_add(&self, val: T, _: Ordering) -> T { + let old = self.0.get(); + self.0.set(old + val); + old + } + } + + pub type AtomicUsize = Atomic; + pub type AtomicBool = Atomic; + pub type AtomicU64 = Atomic; + pub use self::serial_join as join; pub use self::serial_scope as scope; @@ -170,47 +221,6 @@ cfg_if! { MTLock(self.0.clone()) } } - - pub struct LockCell(Cell); - - impl LockCell { - #[inline(always)] - pub fn new(inner: T) -> Self { - LockCell(Cell::new(inner)) - } - - #[inline(always)] - pub fn into_inner(self) -> T { - self.0.into_inner() - } - - #[inline(always)] - pub fn set(&self, new_inner: T) { - self.0.set(new_inner); - } - - #[inline(always)] - pub fn get(&self) -> T where T: Copy { - self.0.get() - } - - #[inline(always)] - pub fn set_mut(&mut self, new_inner: T) { - self.0.set(new_inner); - } - - #[inline(always)] - pub fn get_mut(&mut self) -> T where T: Copy { - self.0.get() - } - } - - impl LockCell> { - #[inline(always)] - pub fn take(&self) -> Option { - unsafe { (*self.0.as_ptr()).take() } - } - } } else { pub use std::marker::Send as Send; pub use std::marker::Sync as Sync; @@ -223,6 +233,8 @@ cfg_if! { pub use parking_lot::MutexGuard as LockGuard; pub use parking_lot::MappedMutexGuard as MappedLockGuard; + pub use std::sync::atomic::{AtomicBool, AtomicUsize, AtomicU64}; + pub use std::sync::Arc as Lrc; pub use std::sync::Weak as Weak; @@ -288,47 +300,6 @@ cfg_if! { v.erase_send_sync_owner() }} } - - pub struct LockCell(Lock); - - impl LockCell { - #[inline(always)] - pub fn new(inner: T) -> Self { - LockCell(Lock::new(inner)) - } - - #[inline(always)] - pub fn into_inner(self) -> T { - self.0.into_inner() - } - - #[inline(always)] - pub fn set(&self, new_inner: T) { - *self.0.lock() = new_inner; - } - - #[inline(always)] - pub fn get(&self) -> T where T: Copy { - *self.0.lock() - } - - #[inline(always)] - pub fn set_mut(&mut self, new_inner: T) { - *self.0.get_mut() = new_inner; - } - - #[inline(always)] - pub fn get_mut(&mut self) -> T where T: Copy { - *self.0.get_mut() - } - } - - impl LockCell> { - #[inline(always)] - pub fn take(&self) -> Option { - self.0.lock().take() - } - } } } @@ -476,65 +447,6 @@ impl Once { } } -impl Debug for LockCell { - fn fmt(&self, f: &mut Formatter) -> fmt::Result { - f.debug_struct("LockCell") - .field("value", &self.get()) - .finish() - } -} - -impl Default for LockCell { - /// Creates a `LockCell`, with the `Default` value for T. - #[inline] - fn default() -> LockCell { - LockCell::new(Default::default()) - } -} - -impl PartialEq for LockCell { - #[inline] - fn eq(&self, other: &LockCell) -> bool { - self.get() == other.get() - } -} - -impl Eq for LockCell {} - -impl PartialOrd for LockCell { - #[inline] - fn partial_cmp(&self, other: &LockCell) -> Option { - self.get().partial_cmp(&other.get()) - } - - #[inline] - fn lt(&self, other: &LockCell) -> bool { - self.get() < other.get() - } - - #[inline] - fn le(&self, other: &LockCell) -> bool { - self.get() <= other.get() - } - - #[inline] - fn gt(&self, other: &LockCell) -> bool { - self.get() > other.get() - } - - #[inline] - fn ge(&self, other: &LockCell) -> bool { - self.get() >= other.get() - } -} - -impl Ord for LockCell { - #[inline] - fn cmp(&self, other: &LockCell) -> Ordering { - self.get().cmp(&other.get()) - } -} - #[derive(Debug)] pub struct Lock(InnerLock); diff --git a/src/librustc_driver/lib.rs b/src/librustc_driver/lib.rs index 39777e0a65b50..a2fae632e1e06 100644 --- a/src/librustc_driver/lib.rs +++ b/src/librustc_driver/lib.rs @@ -27,6 +27,7 @@ #![feature(set_stdio)] #![feature(rustc_stack_internals)] #![feature(no_debug)] +#![feature(integer_atomics)] #![recursion_limit="256"] @@ -78,7 +79,7 @@ use pretty::{PpMode, UserIdentifiedItem}; use rustc_resolve as resolve; use rustc_save_analysis as save; use rustc_save_analysis::DumpHandler; -use rustc_data_structures::sync::{self, Lrc}; +use rustc_data_structures::sync::{self, Lrc, Ordering::SeqCst}; use rustc_data_structures::OnDrop; use rustc::session::{self, config, Session, build_session, CompileResult}; use rustc::session::CompileIncomplete; @@ -954,7 +955,7 @@ impl<'a> CompilerCalls<'a> for RustcDefaultCalls { let sess = state.session; eprintln!("Fuel used by {}: {}", sess.print_fuel_crate.as_ref().unwrap(), - sess.print_fuel.get()); + sess.print_fuel.load(SeqCst)); } } control diff --git a/src/librustc_errors/lib.rs b/src/librustc_errors/lib.rs index b6528cbe2c810..59fa78a85f633 100644 --- a/src/librustc_errors/lib.rs +++ b/src/librustc_errors/lib.rs @@ -36,15 +36,13 @@ use self::Level::*; use emitter::{Emitter, EmitterWriter}; -use rustc_data_structures::sync::{self, Lrc, Lock, LockCell}; +use rustc_data_structures::sync::{self, Lrc, Lock, AtomicUsize, AtomicBool, SeqCst}; use rustc_data_structures::fx::FxHashSet; use rustc_data_structures::stable_hasher::StableHasher; use std::borrow::Cow; use std::cell::Cell; use std::{error, fmt}; -use std::sync::atomic::AtomicUsize; -use std::sync::atomic::Ordering::SeqCst; use std::panic; use termcolor::{ColorSpec, Color}; @@ -281,7 +279,7 @@ pub struct Handler { err_count: AtomicUsize, emitter: Lock>, - continue_after_error: LockCell, + continue_after_error: AtomicBool, delayed_span_bugs: Lock>, // This set contains the `DiagnosticId` of all emitted diagnostics to avoid @@ -380,7 +378,7 @@ impl Handler { flags, err_count: AtomicUsize::new(0), emitter: Lock::new(e), - continue_after_error: LockCell::new(true), + continue_after_error: AtomicBool::new(true), delayed_span_bugs: Lock::new(Vec::new()), taught_diagnostics: Default::default(), emitted_diagnostic_codes: Default::default(), @@ -389,7 +387,7 @@ impl Handler { } pub fn set_continue_after_error(&self, continue_after_error: bool) { - self.continue_after_error.set(continue_after_error); + self.continue_after_error.store(continue_after_error, SeqCst); } /// Resets the diagnostic error count as well as the cached emitted diagnostics. @@ -668,7 +666,7 @@ impl Handler { let mut db = DiagnosticBuilder::new(self, lvl, msg); db.set_span(msp.clone()); db.emit(); - if !self.continue_after_error.get() { + if !self.continue_after_error.load(SeqCst) { self.abort_if_errors(); } } @@ -679,7 +677,7 @@ impl Handler { let mut db = DiagnosticBuilder::new_with_code(self, lvl, Some(code), msg); db.set_span(msp.clone()); db.emit(); - if !self.continue_after_error.get() { + if !self.continue_after_error.load(SeqCst) { self.abort_if_errors(); } }