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提交 c3018387 编写于 作者: S Sean Griffin
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Remove dead code 

These modules were replaced with re-exports from ena
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src/librustc_data_structures/snapshot_vec.rs 已删除 100644 → 0
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// Copyright 2014 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.
//! A utility class for implementing "snapshottable" things; a snapshottable data structure permits
//! you to take a snapshot (via `start_snapshot`) and then, after making some changes, elect either
//! to rollback to the start of the snapshot or commit those changes.
//!
//! This vector is intended to be used as part of an abstraction, not serve as a complete
//! abstraction on its own. As such, while it will roll back most changes on its own, it also
//! supports a `get_mut` operation that gives you an arbitrary mutable pointer into the vector. To
//! ensure that any changes you make this with this pointer are rolled back, you must invoke
//! `record` to record any changes you make and also supplying a delegate capable of reversing
//! those changes.
use self::UndoLog::*;
use std::mem;
use std::ops;
pub enum UndoLog<D: SnapshotVecDelegate> {
/// Indicates where a snapshot started.
OpenSnapshot,
/// Indicates a snapshot that has been committed.
CommittedSnapshot,
/// New variable with given index was created.
NewElem(usize),
/// Variable with given index was changed *from* the given value.
SetElem(usize, D::Value),
/// Extensible set of actions
Other(D::Undo),
}
pub struct SnapshotVec<D: SnapshotVecDelegate> {
values: Vec<D::Value>,
undo_log: Vec<UndoLog<D>>,
}
// Snapshots are tokens that should be created/consumed linearly.
pub struct Snapshot {
// Length of the undo log at the time the snapshot was taken.
length: usize,
}
pub trait SnapshotVecDelegate {
type Value;
type Undo;
fn reverse(values: &mut Vec<Self::Value>, action: Self::Undo);
}
impl<D: SnapshotVecDelegate> SnapshotVec<D> {
pub fn new() -> SnapshotVec<D> {
SnapshotVec {
values: Vec::new(),
undo_log: Vec::new(),
}
}
pub fn with_capacity(n: usize) -> SnapshotVec<D> {
SnapshotVec {
values: Vec::with_capacity(n),
undo_log: Vec::new(),
}
}
fn in_snapshot(&self) -> bool {
!self.undo_log.is_empty()
}
pub fn record(&mut self, action: D::Undo) {
if self.in_snapshot() {
self.undo_log.push(Other(action));
}
}
pub fn len(&self) -> usize {
self.values.len()
}
pub fn push(&mut self, elem: D::Value) -> usize {
let len = self.values.len();
self.values.push(elem);
if self.in_snapshot() {
self.undo_log.push(NewElem(len));
}
len
}
pub fn get(&self, index: usize) -> &D::Value {
&self.values[index]
}
/// Returns a mutable pointer into the vec; whatever changes you make here cannot be undone
/// automatically, so you should be sure call `record()` with some sort of suitable undo
/// action.
pub fn get_mut(&mut self, index: usize) -> &mut D::Value {
&mut self.values[index]
}
/// Updates the element at the given index. The old value will saved (and perhaps restored) if
/// a snapshot is active.
pub fn set(&mut self, index: usize, new_elem: D::Value) {
let old_elem = mem::replace(&mut self.values[index], new_elem);
if self.in_snapshot() {
self.undo_log.push(SetElem(index, old_elem));
}
}
pub fn start_snapshot(&mut self) -> Snapshot {
let length = self.undo_log.len();
self.undo_log.push(OpenSnapshot);
Snapshot { length: length }
}
pub fn actions_since_snapshot(&self, snapshot: &Snapshot) -> &[UndoLog<D>] {
&self.undo_log[snapshot.length..]
}
fn assert_open_snapshot(&self, snapshot: &Snapshot) {
// Or else there was a failure to follow a stack discipline:
assert!(self.undo_log.len() > snapshot.length);
// Invariant established by start_snapshot():
assert!(match self.undo_log[snapshot.length] {
OpenSnapshot => true,
_ => false,
});
}
pub fn rollback_to(&mut self, snapshot: Snapshot) {
debug!("rollback_to({})", snapshot.length);
self.assert_open_snapshot(&snapshot);
while self.undo_log.len() > snapshot.length + 1 {
match self.undo_log.pop().unwrap() {
OpenSnapshot => {
// This indicates a failure to obey the stack discipline.
panic!("Cannot rollback an uncommitted snapshot");
}
CommittedSnapshot => {
// This occurs when there are nested snapshots and
// the inner is committed but outer is rolled back.
}
NewElem(i) => {
self.values.pop();
assert!(self.values.len() == i);
}
SetElem(i, v) => {
self.values[i] = v;
}
Other(u) => {
D::reverse(&mut self.values, u);
}
}
}
let v = self.undo_log.pop().unwrap();
assert!(match v {
OpenSnapshot => true,
_ => false,
});
assert!(self.undo_log.len() == snapshot.length);
}
/// Commits all changes since the last snapshot. Of course, they
/// can still be undone if there is a snapshot further out.
pub fn commit(&mut self, snapshot: Snapshot) {
debug!("commit({})", snapshot.length);
self.assert_open_snapshot(&snapshot);
if snapshot.length == 0 {
// The root snapshot.
self.undo_log.truncate(0);
} else {
self.undo_log[snapshot.length] = CommittedSnapshot;
}
}
}
impl<D: SnapshotVecDelegate> ops::Deref for SnapshotVec<D> {
type Target = [D::Value];
fn deref(&self) -> &[D::Value] {
&*self.values
}
}
impl<D: SnapshotVecDelegate> ops::DerefMut for SnapshotVec<D> {
fn deref_mut(&mut self) -> &mut [D::Value] {
&mut *self.values
}
}
impl<D: SnapshotVecDelegate> ops::Index<usize> for SnapshotVec<D> {
type Output = D::Value;
fn index(&self, index: usize) -> &D::Value {
self.get(index)
}
}
impl<D: SnapshotVecDelegate> ops::IndexMut<usize> for SnapshotVec<D> {
fn index_mut(&mut self, index: usize) -> &mut D::Value {
self.get_mut(index)
}
}
impl<D: SnapshotVecDelegate> Extend<D::Value> for SnapshotVec<D> {
fn extend<T>(&mut self, iterable: T) where T: IntoIterator<Item=D::Value> {
for item in iterable {
self.push(item);
}
}
}
src/librustc_data_structures/unify/mod.rs 已删除 100644 → 0
浏览文件 @ 755bdaa1
// Copyright 2012-2014 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::marker;
use std::fmt::Debug;
use std::marker::PhantomData;
use snapshot_vec as sv;
#[cfg(test)]
mod tests;
/// This trait is implemented by any type that can serve as a type
/// variable. We call such variables *unification keys*. For example,
/// this trait is implemented by `IntVid`, which represents integral
/// variables.
///
/// Each key type has an associated value type `V`. For example, for
/// `IntVid`, this is `Option<IntVarValue>`, representing some
/// (possibly not yet known) sort of integer.
///
/// Clients are expected to provide implementations of this trait; you
/// can see some examples in the `test` module.
pub trait UnifyKey: Copy + Clone + Debug + PartialEq {
type Value: Clone + PartialEq + Debug;
fn index(&self) -> u32;
fn from_index(u: u32) -> Self;
fn tag(k: Option<Self>) -> &'static str;
}
/// This trait is implemented for unify values that can be
/// combined. This relation should be a monoid.
pub trait Combine {
fn combine(&self, other: &Self) -> Self;
}
impl Combine for () {
fn combine(&self, _other: &()) {}
}
/// Value of a unification key. We implement Tarjan's union-find
/// algorithm: when two keys are unified, one of them is converted
/// into a "redirect" pointing at the other. These redirects form a
/// DAG: the roots of the DAG (nodes that are not redirected) are each
/// associated with a value of type `V` and a rank. The rank is used
/// to keep the DAG relatively balanced, which helps keep the running
/// time of the algorithm under control. For more information, see
/// <http://en.wikipedia.org/wiki/Disjoint-set_data_structure>.
#[derive(PartialEq,Clone,Debug)]
pub struct VarValue<K: UnifyKey> {
parent: K, // if equal to self, this is a root
value: K::Value, // value assigned (only relevant to root)
rank: u32, // max depth (only relevant to root)
}
/// Table of unification keys and their values.
pub struct UnificationTable<K: UnifyKey> {
/// Indicates the current value of each key.
values: sv::SnapshotVec<Delegate<K>>,
}
/// At any time, users may snapshot a unification table. The changes
/// made during the snapshot may either be *committed* or *rolled back*.
pub struct Snapshot<K: UnifyKey> {
// Link snapshot to the key type `K` of the table.
marker: marker::PhantomData<K>,
snapshot: sv::Snapshot,
}
#[derive(Copy, Clone)]
struct Delegate<K>(PhantomData<K>);
impl<K: UnifyKey> VarValue<K> {
fn new_var(key: K, value: K::Value) -> VarValue<K> {
VarValue::new(key, value, 0)
}
fn new(parent: K, value: K::Value, rank: u32) -> VarValue<K> {
VarValue {
parent: parent, // this is a root
value,
rank,
}
}
fn redirect(self, to: K) -> VarValue<K> {
VarValue { parent: to, ..self }
}
fn root(self, rank: u32, value: K::Value) -> VarValue<K> {
VarValue {
rank,
value,
..self
}
}
/// Returns the key of this node. Only valid if this is a root
/// node, which you yourself must ensure.
fn key(&self) -> K {
self.parent
}
fn parent(&self, self_key: K) -> Option<K> {
self.if_not_self(self.parent, self_key)
}
fn if_not_self(&self, key: K, self_key: K) -> Option<K> {
if key == self_key { None } else { Some(key) }
}
}
/// We can't use V:LatticeValue, much as I would like to,
/// because frequently the pattern is that V=Option<U> for some
/// other type parameter U, and we have no way to say
/// Option<U>:LatticeValue.
impl<K: UnifyKey> UnificationTable<K> {
pub fn new() -> UnificationTable<K> {
UnificationTable { values: sv::SnapshotVec::new() }
}
/// Starts a new snapshot. Each snapshot must be either
/// rolled back or committed in a "LIFO" (stack) order.
pub fn snapshot(&mut self) -> Snapshot<K> {
Snapshot {
marker: marker::PhantomData::<K>,
snapshot: self.values.start_snapshot(),
}
}
/// Reverses all changes since the last snapshot. Also
/// removes any keys that have been created since then.
pub fn rollback_to(&mut self, snapshot: Snapshot<K>) {
debug!("{}: rollback_to()", UnifyKey::tag(None::<K>));
self.values.rollback_to(snapshot.snapshot);
}
/// Commits all changes since the last snapshot. Of course, they
/// can still be undone if there is a snapshot further out.
pub fn commit(&mut self, snapshot: Snapshot<K>) {
debug!("{}: commit()", UnifyKey::tag(None::<K>));
self.values.commit(snapshot.snapshot);
}
pub fn new_key(&mut self, value: K::Value) -> K {
let len = self.values.len();
let key: K = UnifyKey::from_index(len as u32);
self.values.push(VarValue::new_var(key, value));
debug!("{}: created new key: {:?}", UnifyKey::tag(None::<K>), key);
key
}
/// Find the root node for `vid`. This uses the standard
/// union-find algorithm with path compression:
/// <http://en.wikipedia.org/wiki/Disjoint-set_data_structure>.
///
/// NB. This is a building-block operation and you would probably
/// prefer to call `probe` below.
fn get(&mut self, vid: K) -> VarValue<K> {
let index = vid.index() as usize;
let mut value: VarValue<K> = self.values.get(index).clone();
match value.parent(vid) {
Some(redirect) => {
let root: VarValue<K> = self.get(redirect);
if root.key() != redirect {
// Path compression
value.parent = root.key();
self.values.set(index, value);
}
root
}
None => value,
}
}
fn is_root(&self, key: K) -> bool {
let index = key.index() as usize;
self.values.get(index).parent(key).is_none()
}
/// Sets the value for `vid` to `new_value`. `vid` MUST be a root
/// node! This is an internal operation used to impl other things.
fn set(&mut self, key: K, new_value: VarValue<K>) {
assert!(self.is_root(key));
debug!("Updating variable {:?} to {:?}", key, new_value);
let index = key.index() as usize;
self.values.set(index, new_value);
}
/// Either redirects `node_a` to `node_b` or vice versa, depending
/// on the relative rank. The value associated with the new root
/// will be `new_value`.
///
/// NB: This is the "union" operation of "union-find". It is
/// really more of a building block. If the values associated with
/// your key are non-trivial, you would probably prefer to call
/// `unify_var_var` below.
fn unify(&mut self, root_a: VarValue<K>, root_b: VarValue<K>, new_value: K::Value) -> K {
debug!("unify(root_a(id={:?}, rank={:?}), root_b(id={:?}, rank={:?}))",
root_a.key(),
root_a.rank,
root_b.key(),
root_b.rank);
if root_a.rank > root_b.rank {
// a has greater rank, so a should become b's parent,
// i.e., b should redirect to a.
self.redirect_root(root_a.rank, root_b, root_a, new_value)
} else if root_a.rank < root_b.rank {
// b has greater rank, so a should redirect to b.
self.redirect_root(root_b.rank, root_a, root_b, new_value)
} else {
// If equal, redirect one to the other and increment the
// other's rank.
self.redirect_root(root_a.rank + 1, root_a, root_b, new_value)
}
}
fn redirect_root(&mut self,
new_rank: u32,
old_root: VarValue<K>,
new_root: VarValue<K>,
new_value: K::Value)
-> K {
let old_root_key = old_root.key();
let new_root_key = new_root.key();
self.set(old_root_key, old_root.redirect(new_root_key));
self.set(new_root_key, new_root.root(new_rank, new_value));
new_root_key
}
}
impl<K: UnifyKey> sv::SnapshotVecDelegate for Delegate<K> {
type Value = VarValue<K>;
type Undo = ();
fn reverse(_: &mut Vec<VarValue<K>>, _: ()) {}
}
/// # Base union-find algorithm, where we are just making sets
impl<'tcx, K: UnifyKey> UnificationTable<K>
where K::Value: Combine
{
pub fn union(&mut self, a_id: K, b_id: K) -> K {
let node_a = self.get(a_id);
let node_b = self.get(b_id);
let a_id = node_a.key();
let b_id = node_b.key();
if a_id != b_id {
let new_value = node_a.value.combine(&node_b.value);
self.unify(node_a, node_b, new_value)
} else {
a_id
}
}
pub fn find(&mut self, id: K) -> K {
self.get(id).key()
}
pub fn find_value(&mut self, id: K) -> K::Value {
self.get(id).value
}
#[cfg(test)]
fn unioned(&mut self, a_id: K, b_id: K) -> bool {
self.find(a_id) == self.find(b_id)
}
}
/// # Non-subtyping unification
///
/// Code to handle keys which carry a value, like ints,
/// floats---anything that doesn't have a subtyping relationship we
/// need to worry about.
impl<'tcx, K, V> UnificationTable<K>
where K: UnifyKey<Value = Option<V>>,
V: Clone + PartialEq + Debug
{
pub fn unify_var_var(&mut self, a_id: K, b_id: K) -> Result<K, (V, V)> {
let node_a = self.get(a_id);
let node_b = self.get(b_id);
let a_id = node_a.key();
let b_id = node_b.key();
if a_id == b_id {
return Ok(a_id);
}
let combined = {
match (&node_a.value, &node_b.value) {
(&None, &None) => None,
(&Some(ref v), &None) |
(&None, &Some(ref v)) => Some(v.clone()),
(&Some(ref v1), &Some(ref v2)) => {
if *v1 != *v2 {
return Err((v1.clone(), v2.clone()));
}
Some(v1.clone())
}
}
};
Ok(self.unify(node_a, node_b, combined))
}
/// Sets the value of the key `a_id` to `b`. Because simple keys do not have any subtyping
/// relationships, if `a_id` already has a value, it must be the same as `b`.
pub fn unify_var_value(&mut self, a_id: K, b: V) -> Result<(), (V, V)> {
let mut node_a = self.get(a_id);
match node_a.value {
None => {
node_a.value = Some(b);
self.set(node_a.key(), node_a);
Ok(())
}
Some(ref a_t) => {
if *a_t == b {
Ok(())
} else {
Err((a_t.clone(), b))
}
}
}
}
pub fn has_value(&mut self, id: K) -> bool {
self.get(id).value.is_some()
}
pub fn probe(&mut self, a_id: K) -> Option<V> {
self.get(a_id).value
}
pub fn unsolved_variables(&mut self) -> Vec<K> {
self.values
.iter()
.filter_map(|vv| {
if vv.value.is_some() {
None
} else {
Some(vv.key())
}
})
.collect()
}
}
src/librustc_data_structures/unify/tests.rs 已删除 100644 → 0
浏览文件 @ 755bdaa1
// Copyright 2015 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.
#![allow(non_snake_case)]
extern crate test;
use self::test::Bencher;
use unify::{UnifyKey, UnificationTable};
#[derive(Copy, Clone, Debug, Hash, PartialEq, Eq)]
struct UnitKey(u32);
impl UnifyKey for UnitKey {
type Value = ();
fn index(&self) -> u32 {
self.0
}
fn from_index(u: u32) -> UnitKey {
UnitKey(u)
}
fn tag(_: Option<UnitKey>) -> &'static str {
"UnitKey"
}
}
#[test]
fn basic() {
let mut ut: UnificationTable<UnitKey> = UnificationTable::new();
let k1 = ut.new_key(());
let k2 = ut.new_key(());
assert_eq!(ut.unioned(k1, k2), false);
ut.union(k1, k2);
assert_eq!(ut.unioned(k1, k2), true);
}
#[test]
fn big_array() {
let mut ut: UnificationTable<UnitKey> = UnificationTable::new();
let mut keys = Vec::new();
const MAX: usize = 1 << 15;
for _ in 0..MAX {
keys.push(ut.new_key(()));
}
for i in 1..MAX {
let l = keys[i - 1];
let r = keys[i];
ut.union(l, r);
}
for i in 0..MAX {
assert!(ut.unioned(keys[0], keys[i]));
}
}
#[bench]
fn big_array_bench(b: &mut Bencher) {
let mut ut: UnificationTable<UnitKey> = UnificationTable::new();
let mut keys = Vec::new();
const MAX: usize = 1 << 15;
for _ in 0..MAX {
keys.push(ut.new_key(()));
}
b.iter(|| {
for i in 1..MAX {
let l = keys[i - 1];
let r = keys[i];
ut.union(l, r);
}
for i in 0..MAX {
assert!(ut.unioned(keys[0], keys[i]));
}
})
}
#[test]
fn even_odd() {
let mut ut: UnificationTable<UnitKey> = UnificationTable::new();
let mut keys = Vec::new();
const MAX: usize = 1 << 10;
for i in 0..MAX {
let key = ut.new_key(());
keys.push(key);
if i >= 2 {
ut.union(key, keys[i - 2]);
}
}
for i in 1..MAX {
assert!(!ut.unioned(keys[i - 1], keys[i]));
}
for i in 2..MAX {
assert!(ut.unioned(keys[i - 2], keys[i]));
}
}
#[derive(Copy, Clone, Debug, Hash, PartialEq, Eq)]
struct IntKey(u32);
impl UnifyKey for IntKey {
type Value = Option<i32>;
fn index(&self) -> u32 {
self.0
}
fn from_index(u: u32) -> IntKey {
IntKey(u)
}
fn tag(_: Option<IntKey>) -> &'static str {
"IntKey"
}
}
/// Test unifying a key whose value is `Some(_)` with a key whose value is `None`.
/// Afterwards both should be `Some(_)`.
#[test]
fn unify_key_Some_key_None() {
let mut ut: UnificationTable<IntKey> = UnificationTable::new();
let k1 = ut.new_key(Some(22));
let k2 = ut.new_key(None);
assert!(ut.unify_var_var(k1, k2).is_ok());
assert_eq!(ut.probe(k2), Some(22));
assert_eq!(ut.probe(k1), Some(22));
}
/// Test unifying a key whose value is `None` with a key whose value is `Some(_)`.
/// Afterwards both should be `Some(_)`.
#[test]
fn unify_key_None_key_Some() {
let mut ut: UnificationTable<IntKey> = UnificationTable::new();
let k1 = ut.new_key(Some(22));
let k2 = ut.new_key(None);
assert!(ut.unify_var_var(k2, k1).is_ok());
assert_eq!(ut.probe(k2), Some(22));
assert_eq!(ut.probe(k1), Some(22));
}
/// Test unifying a key whose value is `Some(x)` with a key whose value is `Some(y)`.
/// This should yield an error.
#[test]
fn unify_key_Some_x_key_Some_y() {
let mut ut: UnificationTable<IntKey> = UnificationTable::new();
let k1 = ut.new_key(Some(22));
let k2 = ut.new_key(Some(23));
assert_eq!(ut.unify_var_var(k1, k2), Err((22, 23)));
assert_eq!(ut.unify_var_var(k2, k1), Err((23, 22)));
assert_eq!(ut.probe(k1), Some(22));
assert_eq!(ut.probe(k2), Some(23));
}
/// Test unifying a key whose value is `Some(x)` with a key whose value is `Some(x)`.
/// This should be ok.
#[test]
fn unify_key_Some_x_key_Some_x() {
let mut ut: UnificationTable<IntKey> = UnificationTable::new();
let k1 = ut.new_key(Some(22));
let k2 = ut.new_key(Some(22));
assert!(ut.unify_var_var(k1, k2).is_ok());
assert_eq!(ut.probe(k1), Some(22));
assert_eq!(ut.probe(k2), Some(22));
}
/// Test unifying a key whose value is `None` with a value is `x`.
/// Afterwards key should be `x`.
#[test]
fn unify_key_None_val() {
let mut ut: UnificationTable<IntKey> = UnificationTable::new();
let k1 = ut.new_key(None);
assert!(ut.unify_var_value(k1, 22).is_ok());
assert_eq!(ut.probe(k1), Some(22));
}
/// Test unifying a key whose value is `Some(x)` with the value `y`.
/// This should yield an error.
#[test]
fn unify_key_Some_x_val_y() {
let mut ut: UnificationTable<IntKey> = UnificationTable::new();
let k1 = ut.new_key(Some(22));
assert_eq!(ut.unify_var_value(k1, 23), Err((22, 23)));
assert_eq!(ut.probe(k1), Some(22));
}
/// Test unifying a key whose value is `Some(x)` with the value `x`.
/// This should be ok.
#[test]
fn unify_key_Some_x_val_x() {
let mut ut: UnificationTable<IntKey> = UnificationTable::new();
let k1 = ut.new_key(Some(22));
assert!(ut.unify_var_value(k1, 22).is_ok());
assert_eq!(ut.probe(k1), Some(22));
}
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