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Remove RefCells from RegionMaps
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@cramertj @nikomatsakis
cramertj authored and nikomatsakis committed Apr 30, 2017
1 parent eff39b7 commit 119c38e
Showing 1 changed file with 51 additions and 53 deletions.
104 changes: 51 additions & 53 deletions src/librustc/middle/region.rs
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Expand Up @@ -21,7 +21,6 @@ use session::Session;
use util::nodemap::{FxHashMap, NodeMap, NodeSet};
use ty;

use std::cell::RefCell;
use std::collections::hash_map::Entry;
use std::fmt;
use std::mem;
Expand Down Expand Up @@ -50,7 +49,7 @@ impl fmt::Debug for CodeExtent {
let region_maps = tcx.region_maps();
{
let code_extents = &region_maps.code_extents;
if let Some(data) = code_extents.borrow().get(self.0 as usize) {
if let Some(data) = code_extents.get(self.0 as usize) {
write!(f, "/{:?}", data)?;
}
mem::drop(code_extents); // FIXME why is this necessary?
Expand Down Expand Up @@ -258,34 +257,34 @@ impl CodeExtent {

/// The region maps encode information about region relationships.
pub struct RegionMaps {
code_extents: RefCell<Vec<CodeExtentData>>,
code_extent_interner: RefCell<FxHashMap<CodeExtentData, CodeExtent>>,
code_extents: Vec<CodeExtentData>,
code_extent_interner: FxHashMap<CodeExtentData, CodeExtent>,
/// `scope_map` maps from a scope id to the enclosing scope id;
/// this is usually corresponding to the lexical nesting, though
/// in the case of closures the parent scope is the innermost
/// conditional expression or repeating block. (Note that the
/// enclosing scope id for the block associated with a closure is
/// the closure itself.)
scope_map: RefCell<Vec<CodeExtent>>,
scope_map: Vec<CodeExtent>,

/// `var_map` maps from a variable or binding id to the block in
/// which that variable is declared.
var_map: RefCell<NodeMap<CodeExtent>>,
var_map: NodeMap<CodeExtent>,

/// `rvalue_scopes` includes entries for those expressions whose cleanup scope is
/// larger than the default. The map goes from the expression id
/// to the cleanup scope id. For rvalues not present in this
/// table, the appropriate cleanup scope is the innermost
/// enclosing statement, conditional expression, or repeating
/// block (see `terminating_scopes`).
rvalue_scopes: RefCell<NodeMap<CodeExtent>>,
rvalue_scopes: NodeMap<CodeExtent>,

/// Records the value of rvalue scopes before they were shrunk by
/// #36082, for error reporting.
///
/// FIXME: this should be temporary. Remove this by 1.18.0 or
/// so.
shrunk_rvalue_scopes: RefCell<NodeMap<CodeExtent>>,
shrunk_rvalue_scopes: NodeMap<CodeExtent>,

/// Encodes the hierarchy of fn bodies. Every fn body (including
/// closures) forms its own distinct region hierarchy, rooted in
Expand All @@ -297,7 +296,7 @@ pub struct RegionMaps {
/// closure defined by that fn. See the "Modeling closures"
/// section of the README in infer::region_inference for
/// more details.
fn_tree: RefCell<NodeMap<ast::NodeId>>,
fn_tree: NodeMap<ast::NodeId>,
}

#[derive(Debug, Copy, Clone)]
Expand All @@ -321,7 +320,7 @@ struct RegionResolutionVisitor<'hir: 'a, 'a> {
sess: &'a Session,

// Generated maps:
region_maps: &'a RegionMaps,
region_maps: &'a mut RegionMaps,

cx: Context,

Expand Down Expand Up @@ -354,11 +353,11 @@ struct RegionResolutionVisitor<'hir: 'a, 'a> {
impl RegionMaps {
/// create a bogus code extent for the regions in astencode types. Nobody
/// really cares about the contents of these.
pub fn bogus_code_extent(&self, e: CodeExtentData) -> CodeExtent {
pub fn bogus_code_extent(&mut self, e: CodeExtentData) -> CodeExtent {
self.intern_code_extent(e, DUMMY_CODE_EXTENT)
}
pub fn lookup_code_extent(&self, e: CodeExtentData) -> CodeExtent {
match self.code_extent_interner.borrow().get(&e) {
match self.code_extent_interner.get(&e) {
Some(&d) => d,
None => bug!("unknown code extent {:?}", e)
}
Expand All @@ -375,12 +374,12 @@ impl RegionMaps {
self.lookup_code_extent(CodeExtentData::CallSiteScope { fn_id: fn_id, body_id: body_id })
}
pub fn opt_destruction_extent(&self, n: ast::NodeId) -> Option<CodeExtent> {
self.code_extent_interner.borrow().get(&CodeExtentData::DestructionScope(n)).cloned()
self.code_extent_interner.get(&CodeExtentData::DestructionScope(n)).cloned()
}
pub fn intern_code_extent(&self,
pub fn intern_code_extent(&mut self,
e: CodeExtentData,
parent: CodeExtent) -> CodeExtent {
match self.code_extent_interner.borrow_mut().entry(e) {
match self.code_extent_interner.entry(e) {
Entry::Occupied(o) => {
// this can happen when the bogus code extents from tydecode
// have (bogus) NodeId-s that overlap items created during
Expand All @@ -392,91 +391,90 @@ impl RegionMaps {
info!("CodeExtent({}) = {:?} [parent={}] BOGUS!",
idx.0, e, parent.0);
} else {
assert_eq!(self.scope_map.borrow()[idx.0 as usize],
assert_eq!(self.scope_map[idx.0 as usize],
DUMMY_CODE_EXTENT);
info!("CodeExtent({}) = {:?} [parent={}] RECLAIMED!",
idx.0, e, parent.0);
self.scope_map.borrow_mut()[idx.0 as usize] = parent;
self.scope_map[idx.0 as usize] = parent;
}
idx
}
Entry::Vacant(v) => {
if self.code_extents.borrow().len() > 0xffffffffusize {
if self.code_extents.len() > 0xffffffffusize {
bug!() // should pass a sess,
// but this isn't the only place
}
let idx = CodeExtent(self.code_extents.borrow().len() as u32);
let idx = CodeExtent(self.code_extents.len() as u32);
debug!("CodeExtent({}) = {:?} [parent={}]", idx.0, e, parent.0);
self.code_extents.borrow_mut().push(e);
self.scope_map.borrow_mut().push(parent);
self.code_extents.push(e);
self.scope_map.push(parent);
*v.insert(idx)
}
}
}
pub fn intern_node(&self,
pub fn intern_node(&mut self,
n: ast::NodeId,
parent: CodeExtent) -> CodeExtent {
self.intern_code_extent(CodeExtentData::Misc(n), parent)
}
pub fn code_extent_data(&self, e: CodeExtent) -> CodeExtentData {
self.code_extents.borrow()[e.0 as usize]
self.code_extents[e.0 as usize]
}
pub fn each_encl_scope<E>(&self, mut e:E) where E: FnMut(&CodeExtent, &CodeExtent) {
for child_id in 1..self.code_extents.borrow().len() {
for child_id in 1..self.code_extents.len() {
let child = CodeExtent(child_id as u32);
if let Some(parent) = self.opt_encl_scope(child) {
e(&child, &parent)
}
}
}
pub fn each_var_scope<E>(&self, mut e:E) where E: FnMut(&ast::NodeId, &CodeExtent) {
for (child, parent) in self.var_map.borrow().iter() {
for (child, parent) in self.var_map.iter() {
e(child, parent)
}
}

/// Records that `sub_fn` is defined within `sup_fn`. These ids
/// should be the id of the block that is the fn body, which is
/// also the root of the region hierarchy for that fn.
fn record_fn_parent(&self, sub_fn: ast::NodeId, sup_fn: ast::NodeId) {
fn record_fn_parent(&mut self, sub_fn: ast::NodeId, sup_fn: ast::NodeId) {
debug!("record_fn_parent(sub_fn={:?}, sup_fn={:?})", sub_fn, sup_fn);
assert!(sub_fn != sup_fn);
let previous = self.fn_tree.borrow_mut().insert(sub_fn, sup_fn);
let previous = self.fn_tree.insert(sub_fn, sup_fn);
assert!(previous.is_none());
}

fn fn_is_enclosed_by(&self, mut sub_fn: ast::NodeId, sup_fn: ast::NodeId) -> bool {
let fn_tree = self.fn_tree.borrow();
loop {
if sub_fn == sup_fn { return true; }
match fn_tree.get(&sub_fn) {
match self.fn_tree.get(&sub_fn) {
Some(&s) => { sub_fn = s; }
None => { return false; }
}
}
}

fn record_var_scope(&self, var: ast::NodeId, lifetime: CodeExtent) {
fn record_var_scope(&mut self, var: ast::NodeId, lifetime: CodeExtent) {
debug!("record_var_scope(sub={:?}, sup={:?})", var, lifetime);
assert!(var != lifetime.node_id(self));
self.var_map.borrow_mut().insert(var, lifetime);
self.var_map.insert(var, lifetime);
}

fn record_rvalue_scope(&self, var: ast::NodeId, lifetime: CodeExtent) {
fn record_rvalue_scope(&mut self, var: ast::NodeId, lifetime: CodeExtent) {
debug!("record_rvalue_scope(sub={:?}, sup={:?})", var, lifetime);
assert!(var != lifetime.node_id(self));
self.rvalue_scopes.borrow_mut().insert(var, lifetime);
self.rvalue_scopes.insert(var, lifetime);
}

fn record_shrunk_rvalue_scope(&self, var: ast::NodeId, lifetime: CodeExtent) {
fn record_shrunk_rvalue_scope(&mut self, var: ast::NodeId, lifetime: CodeExtent) {
debug!("record_rvalue_scope(sub={:?}, sup={:?})", var, lifetime);
assert!(var != lifetime.node_id(self));
self.shrunk_rvalue_scopes.borrow_mut().insert(var, lifetime);
self.shrunk_rvalue_scopes.insert(var, lifetime);
}

pub fn opt_encl_scope(&self, id: CodeExtent) -> Option<CodeExtent> {
//! Returns the narrowest scope that encloses `id`, if any.
self.scope_map.borrow()[id.0 as usize].into_option()
self.scope_map[id.0 as usize].into_option()
}

#[allow(dead_code)] // used in cfg
Expand All @@ -487,15 +485,15 @@ impl RegionMaps {

/// Returns the lifetime of the local variable `var_id`
pub fn var_scope(&self, var_id: ast::NodeId) -> CodeExtent {
match self.var_map.borrow().get(&var_id) {
match self.var_map.get(&var_id) {
Some(&r) => r,
None => { bug!("no enclosing scope for id {:?}", var_id); }
}
}

pub fn temporary_scope2(&self, expr_id: ast::NodeId) -> (Option<CodeExtent>, bool) {
let temporary_scope = self.temporary_scope(expr_id);
let was_shrunk = match self.shrunk_rvalue_scopes.borrow().get(&expr_id) {
let was_shrunk = match self.shrunk_rvalue_scopes.get(&expr_id) {
Some(&s) => {
info!("temporary_scope2({:?}, scope={:?}, shrunk={:?})",
expr_id, temporary_scope, s);
Expand All @@ -513,21 +511,21 @@ impl RegionMaps {
let temporary_scope = self.temporary_scope(expr_id);
(temporary_scope,
self.shrunk_rvalue_scopes
.borrow().get(&expr_id).cloned()
.get(&expr_id).cloned()
.or(temporary_scope))
}

pub fn temporary_scope(&self, expr_id: ast::NodeId) -> Option<CodeExtent> {
//! Returns the scope when temp created by expr_id will be cleaned up

// check for a designated rvalue scope
if let Some(&s) = self.rvalue_scopes.borrow().get(&expr_id) {
if let Some(&s) = self.rvalue_scopes.get(&expr_id) {
debug!("temporary_scope({:?}) = {:?} [custom]", expr_id, s);
return Some(s);
}

let scope_map : &[CodeExtent] = &self.scope_map.borrow();
let code_extents: &[CodeExtentData] = &self.code_extents.borrow();
let scope_map : &[CodeExtent] = &self.scope_map;
let code_extents: &[CodeExtentData] = &self.code_extents;

// else, locate the innermost terminating scope
// if there's one. Static items, for instance, won't
Expand Down Expand Up @@ -601,7 +599,7 @@ impl RegionMaps {
let mut a_vec: Vec<CodeExtent> = vec![];
let mut b_buf: [CodeExtent; 32] = [ROOT_CODE_EXTENT; 32];
let mut b_vec: Vec<CodeExtent> = vec![];
let scope_map : &[CodeExtent] = &self.scope_map.borrow();
let scope_map : &[CodeExtent] = &self.scope_map;
let a_ancestors = ancestors_of(scope_map,
scope_a, &mut a_buf, &mut a_vec);
let b_ancestors = ancestors_of(scope_map,
Expand Down Expand Up @@ -1216,7 +1214,7 @@ impl<'hir, 'a> RegionResolutionVisitor<'hir, 'a> {
// functions put their destruction scopes *inside* their parameter
// scopes.
let scope = CodeExtentData::DestructionScope(id);
if !self.region_maps.code_extent_interner.borrow().contains_key(&scope) {
if !self.region_maps.code_extent_interner.contains_key(&scope) {
self.region_maps.intern_code_extent(scope, ROOT_CODE_EXTENT);
}
}
Expand Down Expand Up @@ -1278,14 +1276,14 @@ fn region_resolve_crate<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, crate_num: CrateN

let krate = hir_map.krate();

let maps = RegionMaps {
code_extents: RefCell::new(vec![]),
code_extent_interner: RefCell::new(FxHashMap()),
scope_map: RefCell::new(vec![]),
var_map: RefCell::new(NodeMap()),
rvalue_scopes: RefCell::new(NodeMap()),
shrunk_rvalue_scopes: RefCell::new(NodeMap()),
fn_tree: RefCell::new(NodeMap()),
let mut maps = RegionMaps {
code_extents: vec![],
code_extent_interner: FxHashMap(),
scope_map: vec![],
var_map: NodeMap(),
rvalue_scopes: NodeMap(),
shrunk_rvalue_scopes: NodeMap(),
fn_tree: NodeMap(),
};
let root_extent = maps.bogus_code_extent(
CodeExtentData::DestructionScope(ast::DUMMY_NODE_ID));
Expand All @@ -1296,7 +1294,7 @@ fn region_resolve_crate<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, crate_num: CrateN
{
let mut visitor = RegionResolutionVisitor {
sess: sess,
region_maps: &maps,
region_maps: &mut maps,
map: hir_map,
cx: Context {
root_id: None,
Expand Down

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