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Refactor and fix FIXME's in mtwt hygiene code

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- Moves mtwt hygiene code into its own file
- Fixes FIXME's which leads to ~2x speed gain in expansion pass
- It is now @-free
This commit is contained in:
Edward Wang
2014-02-25 04:47:19 +08:00
parent ea71a08f6b
commit 2302ce903d
8 changed files with 558 additions and 562 deletions
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458
src/libsyntax/ast_util.rs
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@@ -18,11 +18,9 @@ use print::pprust;
use visit::Visitor;
use visit;
use std::cell::{Cell, RefCell};
use std::cell::Cell;
use std::cmp;
use collections::HashMap;
use std::u32;
use std::local_data;
use std::vec_ng::Vec;
pub fn path_name_i(idents: &[Ident]) -> ~str {
@@ -651,251 +649,6 @@ pub fn pat_is_ident(pat: @ast::Pat) -> bool {
}
}
// HYGIENE FUNCTIONS
/// Extend a syntax context with a given mark
pub fn new_mark(m:Mrk, tail:SyntaxContext) -> SyntaxContext {
new_mark_internal(m,tail,get_sctable())
}
// Extend a syntax context with a given mark and table
// FIXME #8215 : currently pub to allow testing
pub fn new_mark_internal(m: Mrk, tail: SyntaxContext, table: &SCTable)
-> SyntaxContext {
let key = (tail,m);
// FIXME #5074 : can't use more natural style because we're missing
// flow-sensitivity. Results in two lookups on a hash table hit.
// also applies to new_rename_internal, below.
// let try_lookup = table.mark_memo.find(&key);
let mut mark_memo = table.mark_memo.borrow_mut();
match mark_memo.get().contains_key(&key) {
false => {
let new_idx = {
let mut table = table.table.borrow_mut();
idx_push(table.get(), Mark(m,tail))
};
mark_memo.get().insert(key,new_idx);
new_idx
}
true => {
match mark_memo.get().find(&key) {
None => fail!("internal error: key disappeared 2013042901"),
Some(idxptr) => {*idxptr}
}
}
}
}
/// Extend a syntax context with a given rename
pub fn new_rename(id:Ident, to:Name, tail:SyntaxContext) -> SyntaxContext {
new_rename_internal(id, to, tail, get_sctable())
}
// Extend a syntax context with a given rename and sctable
// FIXME #8215 : currently pub to allow testing
pub fn new_rename_internal(id: Ident,
to: Name,
tail: SyntaxContext,
table: &SCTable)
-> SyntaxContext {
let key = (tail,id,to);
// FIXME #5074
//let try_lookup = table.rename_memo.find(&key);
let mut rename_memo = table.rename_memo.borrow_mut();
match rename_memo.get().contains_key(&key) {
false => {
let new_idx = {
let mut table = table.table.borrow_mut();
idx_push(table.get(), Rename(id,to,tail))
};
rename_memo.get().insert(key,new_idx);
new_idx
}
true => {
match rename_memo.get().find(&key) {
None => fail!("internal error: key disappeared 2013042902"),
Some(idxptr) => {*idxptr}
}
}
}
}
/// Make a fresh syntax context table with EmptyCtxt in slot zero
/// and IllegalCtxt in slot one.
// FIXME #8215 : currently pub to allow testing
pub fn new_sctable_internal() -> SCTable {
SCTable {
table: RefCell::new(vec!(EmptyCtxt,IllegalCtxt)),
mark_memo: RefCell::new(HashMap::new()),
rename_memo: RefCell::new(HashMap::new()),
}
}
// fetch the SCTable from TLS, create one if it doesn't yet exist.
pub fn get_sctable() -> @SCTable {
local_data_key!(sctable_key: @@SCTable)
match local_data::get(sctable_key, |k| k.map(|k| *k)) {
None => {
let new_table = @@new_sctable_internal();
local_data::set(sctable_key,new_table);
*new_table
},
Some(intr) => *intr
}
}
/// print out an SCTable for debugging
pub fn display_sctable(table : &SCTable) {
error!("SC table:");
let table = table.table.borrow();
for (idx,val) in table.get().iter().enumerate() {
error!("{:4u} : {:?}",idx,val);
}
}
/// Add a value to the end of a vec, return its index
fn idx_push<T>(vec: &mut Vec<T> , val: T) -> u32 {
vec.push(val);
(vec.len() - 1) as u32
}
/// Resolve a syntax object to a name, per MTWT.
pub fn mtwt_resolve(id : Ident) -> Name {
let resolve_table = get_resolve_table();
let mut resolve_table = resolve_table.borrow_mut();
resolve_internal(id, get_sctable(), resolve_table.get())
}
// FIXME #8215: must be pub for testing
pub type ResolveTable = HashMap<(Name,SyntaxContext),Name>;
// okay, I admit, putting this in TLS is not so nice:
// fetch the SCTable from TLS, create one if it doesn't yet exist.
pub fn get_resolve_table() -> @RefCell<ResolveTable> {
local_data_key!(resolve_table_key: @@RefCell<ResolveTable>)
match local_data::get(resolve_table_key, |k| k.map(|k| *k)) {
None => {
let new_table = @@RefCell::new(HashMap::new());
local_data::set(resolve_table_key, new_table);
*new_table
},
Some(intr) => *intr
}
}
// Resolve a syntax object to a name, per MTWT.
// adding memoization to possibly resolve 500+ seconds in resolve for librustc (!)
// FIXME #8215 : currently pub to allow testing
pub fn resolve_internal(id : Ident,
table : &SCTable,
resolve_table : &mut ResolveTable) -> Name {
let key = (id.name,id.ctxt);
match resolve_table.contains_key(&key) {
false => {
let resolved = {
let result = {
let table = table.table.borrow();
*table.get().get(id.ctxt as uint)
};
match result {
EmptyCtxt => id.name,
// ignore marks here:
Mark(_,subctxt) =>
resolve_internal(Ident{name:id.name, ctxt: subctxt},table,resolve_table),
// do the rename if necessary:
Rename(Ident{name,ctxt},toname,subctxt) => {
let resolvedfrom =
resolve_internal(Ident{name:name,ctxt:ctxt},table,resolve_table);
let resolvedthis =
resolve_internal(Ident{name:id.name,ctxt:subctxt},table,resolve_table);
if (resolvedthis == resolvedfrom)
&& (marksof(ctxt,resolvedthis,table)
== marksof(subctxt,resolvedthis,table)) {
toname
} else {
resolvedthis
}
}
IllegalCtxt() => fail!("expected resolvable context, got IllegalCtxt")
}
};
resolve_table.insert(key,resolved);
resolved
}
true => {
// it's guaranteed to be there, because we just checked that it was
// there and we never remove anything from the table:
*(resolve_table.find(&key).unwrap())
}
}
}
/// Compute the marks associated with a syntax context.
pub fn mtwt_marksof(ctxt: SyntaxContext, stopname: Name) -> Vec<Mrk> {
marksof(ctxt, stopname, get_sctable())
}
// the internal function for computing marks
// it's not clear to me whether it's better to use a [] mutable
// vector or a cons-list for this.
pub fn marksof(ctxt: SyntaxContext, stopname: Name, table: &SCTable) -> Vec<Mrk> {
let mut result = Vec::new();
let mut loopvar = ctxt;
loop {
let table_entry = {
let table = table.table.borrow();
*table.get().get(loopvar as uint)
};
match table_entry {
EmptyCtxt => {
return result;
},
Mark(mark, tl) => {
xorPush(&mut result, mark);
loopvar = tl;
},
Rename(_,name,tl) => {
// see MTWT for details on the purpose of the stopname.
// short version: it prevents duplication of effort.
if name == stopname {
return result;
} else {
loopvar = tl;
}
}
IllegalCtxt => fail!("expected resolvable context, got IllegalCtxt")
}
}
}
/// Return the outer mark for a context with a mark at the outside.
/// FAILS when outside is not a mark.
pub fn mtwt_outer_mark(ctxt: SyntaxContext) -> Mrk {
let sctable = get_sctable();
let table = sctable.table.borrow();
match *table.get().get(ctxt as uint) {
ast::Mark(mrk,_) => mrk,
_ => fail!("can't retrieve outer mark when outside is not a mark")
}
}
/// Push a name... unless it matches the one on top, in which
/// case pop and discard (so two of the same marks cancel)
pub fn xorPush(marks: &mut Vec<Mrk> , mark: Mrk) {
if (marks.len() > 0) && (getLast(marks) == mark) {
marks.pop().unwrap();
} else {
marks.push(mark);
}
}
// get the last element of a mutable array.
// FIXME #4903: , must be a separate procedure for now.
pub fn getLast(arr: &Vec<Mrk> ) -> Mrk {
*arr.last().unwrap()
}
// are two paths equal when compared unhygienically?
// since I'm using this to replace ==, it seems appropriate
// to compare the span, global, etc. fields as well.
@@ -937,9 +690,6 @@ mod test {
use ast::*;
use super::*;
use opt_vec;
use collections::HashMap;
use std::vec_ng::Vec;
fn ident_to_segment(id : &Ident) -> PathSegment {
PathSegment {identifier:id.clone(),
@@ -957,210 +707,4 @@ mod test {
[Ident{name:3,ctxt:104},
Ident{name:77,ctxt:182}].map(ident_to_segment)));
}
#[test] fn xorpush_test () {
let mut s = Vec::new();
xorPush(&mut s, 14);
assert_eq!(s.clone(), vec!(14));
xorPush(&mut s, 14);
assert_eq!(s.clone(), Vec::new());
xorPush(&mut s, 14);
assert_eq!(s.clone(), vec!(14));
xorPush(&mut s, 15);
assert_eq!(s.clone(), vec!(14, 15));
xorPush(&mut s, 16);
assert_eq!(s.clone(), vec!(14, 15, 16));
xorPush(&mut s, 16);
assert_eq!(s.clone(), vec!(14, 15));
xorPush(&mut s, 15);
assert_eq!(s.clone(), vec!(14));
}
fn id(n: Name, s: SyntaxContext) -> Ident {
Ident {name: n, ctxt: s}
}
// because of the SCTable, I now need a tidy way of
// creating syntax objects. Sigh.
#[deriving(Clone, Eq, Show)]
enum TestSC {
M(Mrk),
R(Ident,Name)
}
// unfold a vector of TestSC values into a SCTable,
// returning the resulting index
fn unfold_test_sc(tscs : Vec<TestSC> , tail: SyntaxContext, table: &SCTable)
-> SyntaxContext {
tscs.rev_iter().fold(tail, |tail : SyntaxContext, tsc : &TestSC|
{match *tsc {
M(mrk) => new_mark_internal(mrk,tail,table),
R(ident,name) => new_rename_internal(ident,name,tail,table)}})
}
// gather a SyntaxContext back into a vector of TestSCs
fn refold_test_sc(mut sc: SyntaxContext, table : &SCTable) -> Vec<TestSC> {
let mut result = Vec::new();
loop {
let table = table.table.borrow();
match *table.get().get(sc as uint) {
EmptyCtxt => {return result;},
Mark(mrk,tail) => {
result.push(M(mrk));
sc = tail;
continue;
},
Rename(id,name,tail) => {
result.push(R(id,name));
sc = tail;
continue;
}
IllegalCtxt => fail!("expected resolvable context, got IllegalCtxt")
}
}
}
#[test] fn test_unfold_refold(){
let mut t = new_sctable_internal();
let test_sc = vec!(M(3),R(id(101,0),14),M(9));
assert_eq!(unfold_test_sc(test_sc.clone(),EMPTY_CTXT,&mut t),4);
{
let table = t.table.borrow();
assert!(*table.get().get(2) == Mark(9,0));
assert!(*table.get().get(3) == Rename(id(101,0),14,2));
assert!(*table.get().get(4) == Mark(3,3));
}
assert_eq!(refold_test_sc(4,&t),test_sc);
}
// extend a syntax context with a sequence of marks given
// in a vector. v[0] will be the outermost mark.
fn unfold_marks(mrks: Vec<Mrk> , tail: SyntaxContext, table: &SCTable)
-> SyntaxContext {
mrks.rev_iter().fold(tail, |tail:SyntaxContext, mrk:&Mrk|
{new_mark_internal(*mrk,tail,table)})
}
#[test] fn unfold_marks_test() {
let mut t = new_sctable_internal();
assert_eq!(unfold_marks(vec!(3,7),EMPTY_CTXT,&mut t),3);
{
let table = t.table.borrow();
assert!(*table.get().get(2) == Mark(7,0));
assert!(*table.get().get(3) == Mark(3,2));
}
}
#[test] fn test_marksof () {
let stopname = 242;
let name1 = 243;
let mut t = new_sctable_internal();
assert_eq!(marksof (EMPTY_CTXT,stopname,&t),Vec::new());
// FIXME #5074: ANF'd to dodge nested calls
{ let ans = unfold_marks(vec!(4,98),EMPTY_CTXT,&mut t);
assert_eq! (marksof (ans,stopname,&t),vec!(4,98));}
// does xoring work?
{ let ans = unfold_marks(vec!(5,5,16),EMPTY_CTXT,&mut t);
assert_eq! (marksof (ans,stopname,&t), vec!(16));}
// does nested xoring work?
{ let ans = unfold_marks(vec!(5,10,10,5,16),EMPTY_CTXT,&mut t);
assert_eq! (marksof (ans, stopname,&t), vec!(16));}
// rename where stop doesn't match:
{ let chain = vec!(M(9),
R(id(name1,
new_mark_internal (4, EMPTY_CTXT,&mut t)),
100101102),
M(14));
let ans = unfold_test_sc(chain,EMPTY_CTXT,&mut t);
assert_eq! (marksof (ans, stopname, &t), vec!(9,14));}
// rename where stop does match
{ let name1sc = new_mark_internal(4, EMPTY_CTXT, &mut t);
let chain = vec!(M(9),
R(id(name1, name1sc),
stopname),
M(14));
let ans = unfold_test_sc(chain,EMPTY_CTXT,&mut t);
assert_eq! (marksof (ans, stopname, &t), vec!(9)); }
}
#[test] fn resolve_tests () {
let a = 40;
let mut t = new_sctable_internal();
let mut rt = HashMap::new();
// - ctxt is MT
assert_eq!(resolve_internal(id(a,EMPTY_CTXT),&mut t, &mut rt),a);
// - simple ignored marks
{ let sc = unfold_marks(vec!(1,2,3),EMPTY_CTXT,&mut t);
assert_eq!(resolve_internal(id(a,sc),&mut t, &mut rt),a);}
// - orthogonal rename where names don't match
{ let sc = unfold_test_sc(vec!(R(id(50,EMPTY_CTXT),51),M(12)),EMPTY_CTXT,&mut t);
assert_eq!(resolve_internal(id(a,sc),&mut t, &mut rt),a);}
// - rename where names do match, but marks don't
{ let sc1 = new_mark_internal(1,EMPTY_CTXT,&mut t);
let sc = unfold_test_sc(vec!(R(id(a,sc1),50),
M(1),
M(2)),
EMPTY_CTXT,&mut t);
assert_eq!(resolve_internal(id(a,sc),&mut t, &mut rt), a);}
// - rename where names and marks match
{ let sc1 = unfold_test_sc(vec!(M(1),M(2)),EMPTY_CTXT,&mut t);
let sc = unfold_test_sc(vec!(R(id(a,sc1),50),M(1),M(2)),EMPTY_CTXT,&mut t);
assert_eq!(resolve_internal(id(a,sc),&mut t, &mut rt), 50); }
// - rename where names and marks match by literal sharing
{ let sc1 = unfold_test_sc(vec!(M(1),M(2)),EMPTY_CTXT,&mut t);
let sc = unfold_test_sc(vec!(R(id(a,sc1),50)),sc1,&mut t);
assert_eq!(resolve_internal(id(a,sc),&mut t, &mut rt), 50); }
// - two renames of the same var.. can only happen if you use
// local-expand to prevent the inner binding from being renamed
// during the rename-pass caused by the first:
println!("about to run bad test");
{ let sc = unfold_test_sc(vec!(R(id(a,EMPTY_CTXT),50),
R(id(a,EMPTY_CTXT),51)),
EMPTY_CTXT,&mut t);
assert_eq!(resolve_internal(id(a,sc),&mut t, &mut rt), 51); }
// the simplest double-rename:
{ let a_to_a50 = new_rename_internal(id(a,EMPTY_CTXT),50,EMPTY_CTXT,&mut t);
let a50_to_a51 = new_rename_internal(id(a,a_to_a50),51,a_to_a50,&mut t);
assert_eq!(resolve_internal(id(a,a50_to_a51),&mut t, &mut rt),51);
// mark on the outside doesn't stop rename:
let sc = new_mark_internal(9,a50_to_a51,&mut t);
assert_eq!(resolve_internal(id(a,sc),&mut t, &mut rt),51);
// but mark on the inside does:
let a50_to_a51_b = unfold_test_sc(vec!(R(id(a,a_to_a50),51),
M(9)),
a_to_a50,
&mut t);
assert_eq!(resolve_internal(id(a,a50_to_a51_b),&mut t, &mut rt),50);}
}
#[test] fn mtwt_resolve_test(){
let a = 40;
assert_eq!(mtwt_resolve(id(a,EMPTY_CTXT)),a);
}
#[test] fn hashing_tests () {
let mut t = new_sctable_internal();
assert_eq!(new_mark_internal(12,EMPTY_CTXT,&mut t),2);
assert_eq!(new_mark_internal(13,EMPTY_CTXT,&mut t),3);
// using the same one again should result in the same index:
assert_eq!(new_mark_internal(12,EMPTY_CTXT,&mut t),2);
// I'm assuming that the rename table will behave the same....
}
#[test] fn resolve_table_hashing_tests() {
let mut t = new_sctable_internal();
let mut rt = HashMap::new();
assert_eq!(rt.len(),0);
resolve_internal(id(30,EMPTY_CTXT),&mut t, &mut rt);
assert_eq!(rt.len(),1);
resolve_internal(id(39,EMPTY_CTXT),&mut t, &mut rt);
assert_eq!(rt.len(),2);
resolve_internal(id(30,EMPTY_CTXT),&mut t, &mut rt);
assert_eq!(rt.len(),2);
}
}