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Rollup merge of rust-lang#56324 - Zoxc:int-ext, r=nikomatsakis
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Use raw_entry for more efficient interning

Fixes rust-lang#56308 (comment)
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@kennytm
kennytm committed Nov 30, 2018
2 parents 2584d92 + 946ea14 commit ecfe721
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Showing 6 changed files with 157 additions and 111 deletions.
2 changes: 2 additions & 0 deletions src/libarena/lib.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -298,6 +298,7 @@ pub struct DroplessArena {
unsafe impl Send for DroplessArena {}

impl Default for DroplessArena {
#[inline]
fn default() -> DroplessArena {
DroplessArena {
ptr: Cell::new(0 as *mut u8),
Expand All @@ -319,6 +320,7 @@ impl DroplessArena {
false
}

#[inline]
fn align(&self, align: usize) {
let final_address = ((self.ptr.get() as usize) + align - 1) & !(align - 1);
self.ptr.set(final_address as *mut u8);
Expand Down
185 changes: 74 additions & 111 deletions src/librustc/ty/context.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -53,6 +53,7 @@ use ty::CanonicalTy;
use ty::CanonicalPolyFnSig;
use util::nodemap::{DefIdMap, DefIdSet, ItemLocalMap};
use util::nodemap::{FxHashMap, FxHashSet};
use rustc_data_structures::interner::HashInterner;
use smallvec::SmallVec;
use rustc_data_structures::stable_hasher::{HashStable, hash_stable_hashmap,
StableHasher, StableHasherResult,
Expand Down Expand Up @@ -113,7 +114,7 @@ pub struct GlobalArenas<'tcx> {
const_allocs: TypedArena<interpret::Allocation>,
}

type InternedSet<'tcx, T> = Lock<FxHashSet<Interned<'tcx, T>>>;
type InternedSet<'tcx, T> = Lock<FxHashMap<Interned<'tcx, T>, ()>>;

pub struct CtxtInterners<'tcx> {
/// The arena that types, regions, etc are allocated from
Expand Down Expand Up @@ -167,51 +168,39 @@ impl<'gcx: 'tcx, 'tcx> CtxtInterners<'tcx> {
// determine that all contents are in the global tcx.
// See comments on Lift for why we can't use that.
if flags.flags.intersects(ty::TypeFlags::KEEP_IN_LOCAL_TCX) {
let mut interner = local.type_.borrow_mut();
if let Some(&Interned(ty)) = interner.get(&st) {
return ty;
}

let ty_struct = TyS {
sty: st,
flags: flags.flags,
outer_exclusive_binder: flags.outer_exclusive_binder,
};
local.type_.borrow_mut().intern(st, |st| {
let ty_struct = TyS {
sty: st,
flags: flags.flags,
outer_exclusive_binder: flags.outer_exclusive_binder,
};

// Make sure we don't end up with inference
// types/regions in the global interner
if local as *const _ as usize == global as *const _ as usize {
bug!("Attempted to intern `{:?}` which contains \
inference types/regions in the global type context",
&ty_struct);
}
// Make sure we don't end up with inference
// types/regions in the global interner
if local as *const _ as usize == global as *const _ as usize {
bug!("Attempted to intern `{:?}` which contains \
inference types/regions in the global type context",
&ty_struct);
}

// Don't be &mut TyS.
let ty: Ty<'tcx> = local.arena.alloc(ty_struct);
interner.insert(Interned(ty));
ty
Interned(local.arena.alloc(ty_struct))
}).0
} else {
let mut interner = global.type_.borrow_mut();
if let Some(&Interned(ty)) = interner.get(&st) {
return ty;
}

let ty_struct = TyS {
sty: st,
flags: flags.flags,
outer_exclusive_binder: flags.outer_exclusive_binder,
};
global.type_.borrow_mut().intern(st, |st| {
let ty_struct = TyS {
sty: st,
flags: flags.flags,
outer_exclusive_binder: flags.outer_exclusive_binder,
};

// This is safe because all the types the ty_struct can point to
// already is in the global arena
let ty_struct: TyS<'gcx> = unsafe {
mem::transmute(ty_struct)
};
// This is safe because all the types the ty_struct can point to
// already is in the global arena
let ty_struct: TyS<'gcx> = unsafe {
mem::transmute(ty_struct)
};

// Don't be &mut TyS.
let ty: Ty<'gcx> = global.arena.alloc(ty_struct);
interner.insert(Interned(ty));
ty
Interned(global.arena.alloc(ty_struct))
}).0
}
}
}
Expand Down Expand Up @@ -827,12 +816,9 @@ impl<'tcx> CommonTypes<'tcx> {
fn new(interners: &CtxtInterners<'tcx>) -> CommonTypes<'tcx> {
let mk = |sty| CtxtInterners::intern_ty(interners, interners, sty);
let mk_region = |r| {
if let Some(r) = interners.region.borrow().get(&r) {
return r.0;
}
let r = interners.arena.alloc(r);
interners.region.borrow_mut().insert(Interned(r));
&*r
interners.region.borrow_mut().intern(r, |r| {
Interned(interners.arena.alloc(r))
}).0
};

CommonTypes {
Expand Down Expand Up @@ -955,14 +941,14 @@ pub struct GlobalCtxt<'tcx> {
/// Data layout specification for the current target.
pub data_layout: TargetDataLayout,

stability_interner: Lock<FxHashSet<&'tcx attr::Stability>>,
stability_interner: Lock<FxHashMap<&'tcx attr::Stability, ()>>,

/// Stores the value of constants (and deduplicates the actual memory)
allocation_interner: Lock<FxHashSet<&'tcx Allocation>>,
allocation_interner: Lock<FxHashMap<&'tcx Allocation, ()>>,

pub alloc_map: Lock<interpret::AllocMap<'tcx, &'tcx Allocation>>,

layout_interner: Lock<FxHashSet<&'tcx LayoutDetails>>,
layout_interner: Lock<FxHashMap<&'tcx LayoutDetails, ()>>,

/// A general purpose channel to throw data out the back towards LLVM worker
/// threads.
Expand Down Expand Up @@ -1045,16 +1031,9 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
self,
alloc: Allocation,
) -> &'gcx Allocation {
let allocs = &mut self.allocation_interner.borrow_mut();
if let Some(alloc) = allocs.get(&alloc) {
return alloc;
}

let interned = self.global_arenas.const_allocs.alloc(alloc);
if let Some(prev) = allocs.replace(interned) { // insert into interner
bug!("Tried to overwrite interned Allocation: {:#?}", prev)
}
interned
self.allocation_interner.borrow_mut().intern(alloc, |alloc| {
self.global_arenas.const_allocs.alloc(alloc)
})
}

/// Allocates a byte or string literal for `mir::interpret`, read-only
Expand All @@ -1066,29 +1045,15 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
}

pub fn intern_stability(self, stab: attr::Stability) -> &'gcx attr::Stability {
let mut stability_interner = self.stability_interner.borrow_mut();
if let Some(st) = stability_interner.get(&stab) {
return st;
}

let interned = self.global_interners.arena.alloc(stab);
if let Some(prev) = stability_interner.replace(interned) {
bug!("Tried to overwrite interned Stability: {:?}", prev)
}
interned
self.stability_interner.borrow_mut().intern(stab, |stab| {
self.global_interners.arena.alloc(stab)
})
}

pub fn intern_layout(self, layout: LayoutDetails) -> &'gcx LayoutDetails {
let mut layout_interner = self.layout_interner.borrow_mut();
if let Some(layout) = layout_interner.get(&layout) {
return layout;
}

let interned = self.global_arenas.layout.alloc(layout);
if let Some(prev) = layout_interner.replace(interned) {
bug!("Tried to overwrite interned Layout: {:?}", prev)
}
interned
self.layout_interner.borrow_mut().intern(layout, |layout| {
self.global_arenas.layout.alloc(layout)
})
}

/// Returns a range of the start/end indices specified with the
Expand Down Expand Up @@ -2198,7 +2163,7 @@ macro_rules! sty_debug_print {
};
$(let mut $variant = total;)*

for &Interned(t) in tcx.interners.type_.borrow().iter() {
for &Interned(t) in tcx.interners.type_.borrow().keys() {
let variant = match t.sty {
ty::Bool | ty::Char | ty::Int(..) | ty::Uint(..) |
ty::Float(..) | ty::Str | ty::Never => continue,
Expand Down Expand Up @@ -2257,6 +2222,13 @@ impl<'a, 'tcx> TyCtxt<'a, 'tcx, 'tcx> {
/// An entry in an interner.
struct Interned<'tcx, T: 'tcx+?Sized>(&'tcx T);

impl<'tcx, T: 'tcx+?Sized> Clone for Interned<'tcx, T> {
fn clone(&self) -> Self {
Interned(self.0)
}
}
impl<'tcx, T: 'tcx+?Sized> Copy for Interned<'tcx, T> {}

// NB: An Interned<Ty> compares and hashes as a sty.
impl<'tcx> PartialEq for Interned<'tcx, TyS<'tcx>> {
fn eq(&self, other: &Interned<'tcx, TyS<'tcx>>) -> bool {
Expand Down Expand Up @@ -2377,37 +2349,28 @@ macro_rules! intern_method {
// determine that all contents are in the global tcx.
// See comments on Lift for why we can't use that.
if ($keep_in_local_tcx)(&v) {
let mut interner = self.interners.$name.borrow_mut();
if let Some(&Interned(v)) = interner.get(key) {
return v;
}

// Make sure we don't end up with inference
// types/regions in the global tcx.
if self.is_global() {
bug!("Attempted to intern `{:?}` which contains \
inference types/regions in the global type context",
v);
}

let i = $alloc_method(&self.interners.arena, v);
interner.insert(Interned(i));
i
self.interners.$name.borrow_mut().intern_ref(key, || {
// Make sure we don't end up with inference
// types/regions in the global tcx.
if self.is_global() {
bug!("Attempted to intern `{:?}` which contains \
inference types/regions in the global type context",
v);
}

Interned($alloc_method(&self.interners.arena, v))
}).0
} else {
let mut interner = self.global_interners.$name.borrow_mut();
if let Some(&Interned(v)) = interner.get(key) {
return v;
}

// This transmutes $alloc<'tcx> to $alloc<'gcx>
let v = unsafe {
mem::transmute(v)
};
let i: &$lt_tcx $ty = $alloc_method(&self.global_interners.arena, v);
// Cast to 'gcx
let i = unsafe { mem::transmute(i) };
interner.insert(Interned(i));
i
self.global_interners.$name.borrow_mut().intern_ref(key, || {
// This transmutes $alloc<'tcx> to $alloc<'gcx>
let v = unsafe {
mem::transmute(v)
};
let i: &$lt_tcx $ty = $alloc_method(&self.global_interners.arena, v);
// Cast to 'gcx
let i = unsafe { mem::transmute(i) };
Interned(i)
}).0
}
}
}
Expand Down
68 changes: 68 additions & 0 deletions src/librustc_data_structures/interner.rs
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Original file line number Diff line number Diff line change
@@ -0,0 +1,68 @@
// Copyright 2018 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.

use std::hash::Hash;
use std::hash::BuildHasher;
use std::hash::Hasher;
use std::collections::HashMap;
use std::collections::hash_map::RawEntryMut;
use std::borrow::Borrow;

pub trait HashInterner<K: Eq + Hash> {
fn intern_ref<Q: ?Sized, F: FnOnce() -> K>(&mut self, value: &Q, make: F) -> K
where K: Borrow<Q>,
Q: Hash + Eq;

fn intern<Q, F: FnOnce(Q) -> K>(&mut self, value: Q, make: F) -> K
where K: Borrow<Q>,
Q: Hash + Eq;
}

impl<K: Eq + Hash + Copy, S: BuildHasher> HashInterner<K> for HashMap<K, (), S> {
#[inline]
fn intern_ref<Q: ?Sized, F: FnOnce() -> K>(&mut self, value: &Q, make: F) -> K
where K: Borrow<Q>,
Q: Hash + Eq
{
let mut hasher = self.hasher().build_hasher();
value.hash(&mut hasher);
let hash = hasher.finish();
let entry = self.raw_entry_mut().from_key_hashed_nocheck(hash, value);

match entry {
RawEntryMut::Occupied(e) => *e.key(),
RawEntryMut::Vacant(e) => {
let v = make();
e.insert_hashed_nocheck(hash, v, ());
v
}
}
}

#[inline]
fn intern<Q, F: FnOnce(Q) -> K>(&mut self, value: Q, make: F) -> K
where K: Borrow<Q>,
Q: Hash + Eq
{
let mut hasher = self.hasher().build_hasher();
value.hash(&mut hasher);
let hash = hasher.finish();
let entry = self.raw_entry_mut().from_key_hashed_nocheck(hash, &value);

match entry {
RawEntryMut::Occupied(e) => *e.key(),
RawEntryMut::Vacant(e) => {
let v = make(value);
e.insert_hashed_nocheck(hash, v, ());
v
}
}
}
}
2 changes: 2 additions & 0 deletions src/librustc_data_structures/lib.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -29,6 +29,7 @@
#![feature(nll)]
#![feature(allow_internal_unstable)]
#![feature(vec_resize_with)]
#![feature(hash_raw_entry)]

#![cfg_attr(unix, feature(libc))]
#![cfg_attr(test, feature(test))]
Expand Down Expand Up @@ -66,6 +67,7 @@ pub mod flock;
pub mod fx;
pub mod graph;
pub mod indexed_vec;
pub mod interner;
pub mod obligation_forest;
pub mod owning_ref;
pub mod ptr_key;
Expand Down
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