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Improve import resolution #31726

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merged 6 commits into from
Mar 5, 2016
Merged

Improve import resolution #31726

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064f17c
Record that an import succeeded or failed in one namespace even while…
jseyfried Feb 13, 2016
6b94bc3
Add an arena for import directives
jseyfried Feb 15, 2016
fb4710c
Add a field in Module for the ResolverArenas
jseyfried Feb 15, 2016
20b99d3
Start importing bindings from globs as soon as the glob path is known.
jseyfried Feb 16, 2016
51ca449
Refactor away define
jseyfried Feb 16, 2016
b3572ae
Finish encapsulating the details of import resolution in resolve_imports
jseyfried Feb 16, 2016
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41 changes: 13 additions & 28 deletions src/librustc_resolve/build_reduced_graph.rs
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Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -98,14 +98,14 @@ impl<'a, 'b:'a, 'tcx:'b> GraphBuilder<'a, 'b, 'tcx> {
fn try_define<T>(&self, parent: Module<'b>, name: Name, ns: Namespace, def: T)
where T: ToNameBinding<'b>
{
let _ = parent.try_define_child(name, ns, self.new_name_binding(def.to_name_binding()));
let _ = parent.try_define_child(name, ns, def.to_name_binding());
}

/// Defines `name` in namespace `ns` of module `parent` to be `def` if it is not yet defined;
/// otherwise, reports an error.
fn define<T: ToNameBinding<'b>>(&self, parent: Module<'b>, name: Name, ns: Namespace, def: T) {
let binding = self.new_name_binding(def.to_name_binding());
let old_binding = match parent.try_define_child(name, ns, binding) {
let binding = def.to_name_binding();
let old_binding = match parent.try_define_child(name, ns, binding.clone()) {
Ok(()) => return,
Err(old_binding) => old_binding,
};
Expand Down Expand Up @@ -207,7 +207,7 @@ impl<'a, 'b:'a, 'tcx:'b> GraphBuilder<'a, 'b, 'tcx> {
ResolutionError::SelfImportsOnlyAllowedWithin);
}

let subclass = SingleImport(binding, source_name);
let subclass = ImportDirectiveSubclass::single(binding, source_name);
self.build_import_directive(parent,
module_path,
subclass,
Expand Down Expand Up @@ -258,9 +258,10 @@ impl<'a, 'b:'a, 'tcx:'b> GraphBuilder<'a, 'b, 'tcx> {
(module_path.to_vec(), name, rename)
}
};
let subclass = ImportDirectiveSubclass::single(rename, name);
self.build_import_directive(parent,
module_path,
SingleImport(rename, name),
subclass,
source_item.span,
source_item.node.id(),
is_public,
Expand Down Expand Up @@ -294,14 +295,6 @@ impl<'a, 'b:'a, 'tcx:'b> GraphBuilder<'a, 'b, 'tcx> {
let module = self.new_extern_crate_module(parent_link, def, is_public, item.id);
self.define(parent, name, TypeNS, (module, sp));

if is_public {
let export = Export { name: name, def_id: def_id };
if let Some(def_id) = parent.def_id() {
let node_id = self.resolver.ast_map.as_local_node_id(def_id).unwrap();
self.export_map.entry(node_id).or_insert(Vec::new()).push(export);
}
}

self.build_reduced_graph_for_external_crate(module);
}
parent
Expand Down Expand Up @@ -683,33 +676,25 @@ impl<'a, 'b:'a, 'tcx:'b> GraphBuilder<'a, 'b, 'tcx> {
id: NodeId,
is_public: bool,
shadowable: Shadowable) {
module_.unresolved_imports
.borrow_mut()
.push(ImportDirective::new(module_path, subclass, span, id, is_public, shadowable));
self.unresolved_imports += 1;

if is_public {
module_.inc_pub_count();
}

// Bump the reference count on the name. Or, if this is a glob, set
// the appropriate flag.

match subclass {
SingleImport(target, _) => {
SingleImport { target, .. } => {
module_.increment_outstanding_references_for(target, ValueNS);
module_.increment_outstanding_references_for(target, TypeNS);
}
GlobImport => {
// Set the glob flag. This tells us that we don't know the
// module's exports ahead of time.

module_.inc_glob_count();
if is_public {
module_.inc_pub_glob_count();
}
module_.inc_glob_count(is_public)
}
}

let directive =
ImportDirective::new(module_path, subclass, span, id, is_public, shadowable);
module_.add_import_directive(directive);
self.unresolved_imports += 1;
}
}

Expand Down
141 changes: 47 additions & 94 deletions src/librustc_resolve/lib.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -18,6 +18,7 @@
#![cfg_attr(not(stage0), deny(warnings))]

#![feature(associated_consts)]
#![feature(borrow_state)]
#![feature(rustc_diagnostic_macros)]
#![feature(rustc_private)]
#![feature(staged_api)]
Expand Down Expand Up @@ -812,7 +813,7 @@ pub struct ModuleS<'a> {
extern_crate_id: Option<NodeId>,

resolutions: RefCell<HashMap<(Name, Namespace), NameResolution<'a>>>,
unresolved_imports: RefCell<Vec<ImportDirective>>,
unresolved_imports: RefCell<Vec<&'a ImportDirective>>,

// The module children of this node, including normal modules and anonymous modules.
// Anonymous children are pseudo-modules that are implicitly created around items
Expand All @@ -832,26 +833,31 @@ pub struct ModuleS<'a> {

shadowed_traits: RefCell<Vec<&'a NameBinding<'a>>>,

// The number of unresolved globs that this module exports.
glob_count: Cell<usize>,
glob_importers: RefCell<Vec<(Module<'a>, &'a ImportDirective)>>,
resolved_globs: RefCell<(Vec<Module<'a>> /* public */, Vec<Module<'a>> /* private */)>,

// The number of unresolved pub imports (both regular and globs) in this module
pub_count: Cell<usize>,
// The number of public glob imports in this module.
public_glob_count: Cell<usize>,

// The number of unresolved pub glob imports in this module
pub_glob_count: Cell<usize>,
// The number of private glob imports in this module.
private_glob_count: Cell<usize>,

// Whether this module is populated. If not populated, any attempt to
// access the children must be preceded with a
// `populate_module_if_necessary` call.
populated: Cell<bool>,

arenas: &'a ResolverArenas<'a>,
}

pub type Module<'a> = &'a ModuleS<'a>;

impl<'a> ModuleS<'a> {

fn new(parent_link: ParentLink<'a>, def: Option<Def>, external: bool, is_public: bool) -> Self {
fn new(parent_link: ParentLink<'a>,
def: Option<Def>,
external: bool,
is_public: bool,
arenas: &'a ResolverArenas<'a>) -> Self {
ModuleS {
parent_link: parent_link,
def: def,
Expand All @@ -861,53 +867,18 @@ impl<'a> ModuleS<'a> {
unresolved_imports: RefCell::new(Vec::new()),
module_children: RefCell::new(NodeMap()),
shadowed_traits: RefCell::new(Vec::new()),
glob_count: Cell::new(0),
pub_count: Cell::new(0),
pub_glob_count: Cell::new(0),
glob_importers: RefCell::new(Vec::new()),
resolved_globs: RefCell::new((Vec::new(), Vec::new())),
public_glob_count: Cell::new(0),
private_glob_count: Cell::new(0),
populated: Cell::new(!external),
arenas: arenas
}
}

fn resolve_name(&self, name: Name, ns: Namespace, allow_private_imports: bool)
-> ResolveResult<&'a NameBinding<'a>> {
let glob_count =
if allow_private_imports { self.glob_count.get() } else { self.pub_glob_count.get() };

self.resolutions.borrow().get(&(name, ns)).cloned().unwrap_or_default().result(glob_count)
.and_then(|binding| {
let allowed = allow_private_imports || !binding.is_import() || binding.is_public();
if allowed { Success(binding) } else { Failed(None) }
})
}

// Define the name or return the existing binding if there is a collision.
fn try_define_child(&self, name: Name, ns: Namespace, binding: &'a NameBinding<'a>)
-> Result<(), &'a NameBinding<'a>> {
let mut children = self.resolutions.borrow_mut();
let resolution = children.entry((name, ns)).or_insert_with(Default::default);

// FIXME #31379: We can use methods from imported traits shadowed by non-import items
if let Some(old_binding) = resolution.binding {
if !old_binding.is_import() && binding.is_import() {
if let Some(Def::Trait(_)) = binding.def() {
self.shadowed_traits.borrow_mut().push(binding);
}
}
}

resolution.try_define(binding)
}

fn increment_outstanding_references_for(&self, name: Name, ns: Namespace) {
let mut children = self.resolutions.borrow_mut();
children.entry((name, ns)).or_insert_with(Default::default).outstanding_references += 1;
}

fn decrement_outstanding_references_for(&self, name: Name, ns: Namespace) {
match self.resolutions.borrow_mut().get_mut(&(name, ns)).unwrap().outstanding_references {
0 => panic!("No more outstanding references!"),
ref mut outstanding_references => { *outstanding_references -= 1; }
}
fn add_import_directive(&self, import_directive: ImportDirective) {
let import_directive = self.arenas.alloc_import_directive(import_directive);
self.unresolved_imports.borrow_mut().push(import_directive);
}

fn for_each_child<F: FnMut(Name, Namespace, &'a NameBinding<'a>)>(&self, mut f: F) {
Expand Down Expand Up @@ -943,26 +914,9 @@ impl<'a> ModuleS<'a> {
}
}

pub fn inc_glob_count(&self) {
self.glob_count.set(self.glob_count.get() + 1);
}
pub fn dec_glob_count(&self) {
assert!(self.glob_count.get() > 0);
self.glob_count.set(self.glob_count.get() - 1);
}
pub fn inc_pub_count(&self) {
self.pub_count.set(self.pub_count.get() + 1);
}
pub fn dec_pub_count(&self) {
assert!(self.pub_count.get() > 0);
self.pub_count.set(self.pub_count.get() - 1);
}
pub fn inc_pub_glob_count(&self) {
self.pub_glob_count.set(self.pub_glob_count.get() + 1);
}
pub fn dec_pub_glob_count(&self) {
assert!(self.pub_glob_count.get() > 0);
self.pub_glob_count.set(self.pub_glob_count.get() - 1);
fn inc_glob_count(&self, is_public: bool) {
let glob_count = if is_public { &self.public_glob_count } else { &self.private_glob_count };
glob_count.set(glob_count.get() + 1);
}
}

Expand Down Expand Up @@ -995,14 +949,14 @@ bitflags! {
}

// Records a possibly-private value, type, or module definition.
#[derive(Debug)]
#[derive(Clone, Debug)]
pub struct NameBinding<'a> {
modifiers: DefModifiers,
kind: NameBindingKind<'a>,
span: Option<Span>,
}

#[derive(Debug)]
#[derive(Clone, Debug)]
enum NameBindingKind<'a> {
Def(Def),
Module(Module<'a>),
Expand Down Expand Up @@ -1167,6 +1121,19 @@ pub struct Resolver<'a, 'tcx: 'a> {
pub struct ResolverArenas<'a> {
modules: arena::TypedArena<ModuleS<'a>>,
name_bindings: arena::TypedArena<NameBinding<'a>>,
import_directives: arena::TypedArena<ImportDirective>,
}

impl<'a> ResolverArenas<'a> {
fn alloc_module(&'a self, module: ModuleS<'a>) -> Module<'a> {
self.modules.alloc(module)
}
fn alloc_name_binding(&'a self, name_binding: NameBinding<'a>) -> &'a NameBinding<'a> {
self.name_bindings.alloc(name_binding)
}
fn alloc_import_directive(&'a self, import_directive: ImportDirective) -> &'a ImportDirective {
self.import_directives.alloc(import_directive)
}
}

#[derive(PartialEq)]
Expand All @@ -1182,8 +1149,9 @@ impl<'a, 'tcx> Resolver<'a, 'tcx> {
arenas: &'a ResolverArenas<'a>)
-> Resolver<'a, 'tcx> {
let root_def_id = ast_map.local_def_id(CRATE_NODE_ID);
let graph_root = ModuleS::new(NoParentLink, Some(Def::Mod(root_def_id)), false, true);
let graph_root = arenas.modules.alloc(graph_root);
let graph_root =
ModuleS::new(NoParentLink, Some(Def::Mod(root_def_id)), false, true, arenas);
let graph_root = arenas.alloc_module(graph_root);

Resolver {
session: session,
Expand Down Expand Up @@ -1234,6 +1202,7 @@ impl<'a, 'tcx> Resolver<'a, 'tcx> {
ResolverArenas {
modules: arena::TypedArena::new(),
name_bindings: arena::TypedArena::new(),
import_directives: arena::TypedArena::new(),
}
}

Expand All @@ -1242,11 +1211,7 @@ impl<'a, 'tcx> Resolver<'a, 'tcx> {
def: Option<Def>,
external: bool,
is_public: bool) -> Module<'a> {
self.arenas.modules.alloc(ModuleS::new(parent_link, def, external, is_public))
}

fn new_name_binding(&self, name_binding: NameBinding<'a>) -> &'a NameBinding<'a> {
self.arenas.name_bindings.alloc(name_binding)
self.arenas.alloc_module(ModuleS::new(parent_link, def, external, is_public, self.arenas))
}

fn new_extern_crate_module(&self,
Expand All @@ -1255,7 +1220,7 @@ impl<'a, 'tcx> Resolver<'a, 'tcx> {
is_public: bool,
local_node_id: NodeId)
-> Module<'a> {
let mut module = ModuleS::new(parent_link, Some(def), false, is_public);
let mut module = ModuleS::new(parent_link, Some(def), false, is_public, self.arenas);
module.extern_crate_id = Some(local_node_id);
self.arenas.modules.alloc(module)
}
Expand Down Expand Up @@ -1626,18 +1591,6 @@ impl<'a, 'tcx> Resolver<'a, 'tcx> {
})
}

fn report_unresolved_imports(&mut self, module_: Module<'a>) {
for import in module_.unresolved_imports.borrow().iter() {
resolve_error(self, import.span, ResolutionError::UnresolvedImport(None));
break;
}

// Descend into children and anonymous children.
for (_, module_) in module_.module_children.borrow().iter() {
self.report_unresolved_imports(module_);
}
}

// AST resolution
//
// We maintain a list of value ribs and type ribs.
Expand Down
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