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Auto merge of #88872 - petrochenkov:getmod2, r=cjgillot
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resolve: Some module-related refactorings

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@bors
bors committed Sep 24, 2021
2 parents f06f9bb + 8f035b8 commit 7342213
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Showing 8 changed files with 178 additions and 193 deletions.
219 changes: 102 additions & 117 deletions compiler/rustc_resolve/src/build_reduced_graph.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -9,11 +9,9 @@ use crate::def_collector::collect_definitions;
use crate::imports::{Import, ImportKind};
use crate::macros::{MacroRulesBinding, MacroRulesScope, MacroRulesScopeRef};
use crate::Namespace::{self, MacroNS, TypeNS, ValueNS};
use crate::{CrateLint, Determinacy, PathResult, ResolutionError, VisResolutionError};
use crate::{
ExternPreludeEntry, ModuleOrUniformRoot, ParentScope, PerNS, Resolver, ResolverArenas,
};
use crate::{Module, ModuleData, ModuleKind, NameBinding, NameBindingKind, Segment, ToNameBinding};
use crate::{CrateLint, Determinacy, ExternPreludeEntry, Module, ModuleKind, ModuleOrUniformRoot};
use crate::{NameBinding, NameBindingKind, ParentScope, PathResult, PerNS, ResolutionError};
use crate::{Resolver, ResolverArenas, Segment, ToNameBinding, VisResolutionError};

use rustc_ast::visit::{self, AssocCtxt, Visitor};
use rustc_ast::{self as ast, AssocItem, AssocItemKind, MetaItemKind, StmtKind};
Expand Down Expand Up @@ -95,100 +93,93 @@ impl<'a> Resolver<'a> {
}

/// Walks up the tree of definitions starting at `def_id`,
/// stopping at the first `DefKind::Mod` encountered
fn nearest_parent_mod(&mut self, def_id: DefId) -> Module<'a> {
let def_key = self.cstore().def_key(def_id);

let mut parent_id = DefId {
krate: def_id.krate,
index: def_key.parent.expect("failed to get parent for module"),
};
// The immediate parent may not be a module
// (e.g. `const _: () = { #[path = "foo.rs"] mod foo; };`)
// Walk up the tree until we hit a module or the crate root.
while parent_id.index != CRATE_DEF_INDEX
&& self.cstore().def_kind(parent_id) != DefKind::Mod
{
let parent_def_key = self.cstore().def_key(parent_id);
parent_id.index = parent_def_key.parent.expect("failed to get parent for module");
/// stopping at the first encountered module.
/// Parent block modules for arbitrary def-ids are not recorded for the local crate,
/// and are not preserved in metadata for foreign crates, so block modules are never
/// returned by this function.
///
/// For the local crate ignoring block modules may be incorrect, so use this method with care.
///
/// For foreign crates block modules can be ignored without introducing observable differences,
/// moreover they has to be ignored right now because they are not kept in metadata.
/// Foreign parent modules are used for resolving names used by foreign macros with def-site
/// hygiene, therefore block module ignorability relies on macros with def-site hygiene and
/// block module parents being unreachable from other crates.
/// Reachable macros with block module parents exist due to `#[macro_export] macro_rules!`,
/// but they cannot use def-site hygiene, so the assumption holds
/// (<https://github.com/rust-lang/rust/pull/77984#issuecomment-712445508>).
fn get_nearest_non_block_module(&mut self, mut def_id: DefId) -> Module<'a> {
loop {
match self.get_module(def_id) {
Some(module) => return module,
None => {
def_id.index =
self.def_key(def_id).parent.expect("non-root `DefId` without parent")
}
}
}
self.get_module(parent_id)
}

pub fn get_module(&mut self, def_id: DefId) -> Module<'a> {
// If this is a local module, it will be in `module_map`, no need to recalculate it.
if let Some(def_id) = def_id.as_local() {
return self.module_map[&def_id];
}
pub fn expect_module(&mut self, def_id: DefId) -> Module<'a> {
self.get_module(def_id).expect("argument `DefId` is not a module")
}

// Cache module resolution
if let Some(&module) = self.extern_module_map.get(&def_id) {
return module;
/// If `def_id` refers to a module (in resolver's sense, i.e. a module item, crate root, enum,
/// or trait), then this function returns that module's resolver representation, otherwise it
/// returns `None`.
/// FIXME: `Module`s for local enums and traits are not currently found.
crate fn get_module(&mut self, def_id: DefId) -> Option<Module<'a>> {
if let module @ Some(..) = self.module_map.get(&def_id) {
return module.copied();
}

let (name, parent) = if def_id.index == CRATE_DEF_INDEX {
// This is the crate root
(self.cstore().crate_name(def_id.krate), None)
} else {
let def_key = self.cstore().def_key(def_id);
let name = def_key
.disambiguated_data
.data
.get_opt_name()
.expect("given a DefId that wasn't a module");

let parent = Some(self.nearest_parent_mod(def_id));
(name, parent)
};
if !def_id.is_local() {
let def_kind = self.cstore().def_kind(def_id);
match def_kind {
DefKind::Mod | DefKind::Enum | DefKind::Trait => {
let def_key = self.cstore().def_key(def_id);
let parent = def_key.parent.map(|index| {
self.get_nearest_non_block_module(DefId { index, krate: def_id.krate })
});
let name = if def_id.index == CRATE_DEF_INDEX {
self.cstore().crate_name(def_id.krate)
} else {
def_key.disambiguated_data.data.get_opt_name().expect("module without name")
};

// Allocate and return a new module with the information we found
let kind = ModuleKind::Def(DefKind::Mod, def_id, name);
let module = self.arenas.alloc_module(ModuleData::new(
parent,
kind,
def_id,
self.cstore().module_expansion_untracked(def_id, &self.session),
self.cstore().get_span_untracked(def_id, &self.session),
));
self.extern_module_map.insert(def_id, module);
module
let module = self.arenas.new_module(
parent,
ModuleKind::Def(def_kind, def_id, name),
self.cstore().module_expansion_untracked(def_id, &self.session),
self.cstore().get_span_untracked(def_id, &self.session),
// FIXME: Account for `#[no_implicit_prelude]` attributes.
parent.map_or(false, |module| module.no_implicit_prelude),
);
self.module_map.insert(def_id, module);
Some(module)
}
_ => None,
}
} else {
None
}
}

crate fn macro_def_scope(&mut self, expn_id: ExpnId) -> Module<'a> {
let def_id = match expn_id.expn_data().macro_def_id {
Some(def_id) => def_id,
None => {
return expn_id
.as_local()
.and_then(|expn_id| self.ast_transform_scopes.get(&expn_id))
.unwrap_or(&self.graph_root);
}
};
self.macro_def_scope_from_def_id(def_id)
crate fn expn_def_scope(&mut self, expn_id: ExpnId) -> Module<'a> {
match expn_id.expn_data().macro_def_id {
Some(def_id) => self.macro_def_scope(def_id),
None => expn_id
.as_local()
.and_then(|expn_id| self.ast_transform_scopes.get(&expn_id))
.unwrap_or(&self.graph_root),
}
}

crate fn macro_def_scope_from_def_id(&mut self, def_id: DefId) -> Module<'a> {
crate fn macro_def_scope(&mut self, def_id: DefId) -> Module<'a> {
if let Some(id) = def_id.as_local() {
self.local_macro_def_scopes[&id]
} else {
// This is not entirely correct - a `macro_rules!` macro may occur
// inside a 'block' module:
//
// ```rust
// const _: () = {
// #[macro_export]
// macro_rules! my_macro {
// () => {};
// }
// `
// We don't record this information for external crates, so
// the module we compute here will be the closest 'mod' item
// (not necesssarily the actual parent of the `macro_rules!`
// macro). `macro_rules!` macros can't use def-site hygiene,
// so this hopefully won't be a problem.
//
// See https://github.com/rust-lang/rust/pull/77984#issuecomment-712445508
self.nearest_parent_mod(def_id)
self.get_nearest_non_block_module(def_id)
}
}

Expand Down Expand Up @@ -274,7 +265,7 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
self.r.visibilities[&def_id.expect_local()]
}
// Otherwise, the visibility is restricted to the nearest parent `mod` item.
_ => ty::Visibility::Restricted(self.parent_scope.module.nearest_parent_mod),
_ => ty::Visibility::Restricted(self.parent_scope.module.nearest_parent_mod()),
})
}
ast::VisibilityKind::Restricted { ref path, id, .. } => {
Expand Down Expand Up @@ -717,7 +708,7 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
local_def_id,
);
self.r.extern_crate_map.insert(local_def_id, crate_id);
self.r.get_module(DefId { krate: crate_id, index: CRATE_DEF_INDEX })
self.r.expect_module(crate_id.as_def_id())
};

let used = self.process_macro_use_imports(item, module);
Expand Down Expand Up @@ -768,21 +759,16 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
}

ItemKind::Mod(..) => {
let module_kind = ModuleKind::Def(DefKind::Mod, def_id, ident.name);
let module = self.r.arenas.alloc_module(ModuleData {
no_implicit_prelude: parent.no_implicit_prelude || {
self.r.session.contains_name(&item.attrs, sym::no_implicit_prelude)
},
..ModuleData::new(
Some(parent),
module_kind,
def_id,
expansion.to_expn_id(),
item.span,
)
});
let module = self.r.arenas.new_module(
Some(parent),
ModuleKind::Def(DefKind::Mod, def_id, ident.name),
expansion.to_expn_id(),
item.span,
parent.no_implicit_prelude
|| self.r.session.contains_name(&item.attrs, sym::no_implicit_prelude),
);
self.r.define(parent, ident, TypeNS, (module, vis, sp, expansion));
self.r.module_map.insert(local_def_id, module);
self.r.module_map.insert(def_id, module);

// Descend into the module.
self.parent_scope.module = module;
Expand Down Expand Up @@ -813,13 +799,12 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
}

ItemKind::Enum(_, _) => {
let module_kind = ModuleKind::Def(DefKind::Enum, def_id, ident.name);
let module = self.r.new_module(
parent,
module_kind,
parent.nearest_parent_mod,
let module = self.r.arenas.new_module(
Some(parent),
ModuleKind::Def(DefKind::Enum, def_id, ident.name),
expansion.to_expn_id(),
item.span,
parent.no_implicit_prelude,
);
self.r.define(parent, ident, TypeNS, (module, vis, sp, expansion));
self.parent_scope.module = module;
Expand Down Expand Up @@ -888,13 +873,12 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {

ItemKind::Trait(..) => {
// Add all the items within to a new module.
let module_kind = ModuleKind::Def(DefKind::Trait, def_id, ident.name);
let module = self.r.new_module(
parent,
module_kind,
parent.nearest_parent_mod,
let module = self.r.arenas.new_module(
Some(parent),
ModuleKind::Def(DefKind::Trait, def_id, ident.name),
expansion.to_expn_id(),
item.span,
parent.no_implicit_prelude,
);
self.r.define(parent, ident, TypeNS, (module, vis, sp, expansion));
self.parent_scope.module = module;
Expand Down Expand Up @@ -932,12 +916,12 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
let parent = self.parent_scope.module;
let expansion = self.parent_scope.expansion;
if self.block_needs_anonymous_module(block) {
let module = self.r.new_module(
parent,
let module = self.r.arenas.new_module(
Some(parent),
ModuleKind::Block(block.id),
parent.nearest_parent_mod,
expansion.to_expn_id(),
block.span,
parent.no_implicit_prelude,
);
self.r.block_map.insert(block.id, module);
self.parent_scope.module = module; // Descend into the block.
Expand All @@ -953,12 +937,13 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
// Record primary definitions.
match res {
Res::Def(kind @ (DefKind::Mod | DefKind::Enum | DefKind::Trait), def_id) => {
let module = self.r.new_module(
parent,
let module = self.r.arenas.new_module(
Some(parent),
ModuleKind::Def(kind, def_id, ident.name),
def_id,
expansion.to_expn_id(),
span,
// FIXME: Account for `#[no_implicit_prelude]` attributes.
parent.no_implicit_prelude,
);
self.r.define(parent, ident, TypeNS, (module, vis, span, expansion));
}
Expand Down
3 changes: 1 addition & 2 deletions compiler/rustc_resolve/src/diagnostics.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -915,8 +915,7 @@ impl<'a> Resolver<'a> {
continue;
}
if let Some(crate_id) = self.crate_loader.maybe_process_path_extern(ident.name) {
let crate_root =
self.get_module(DefId { krate: crate_id, index: CRATE_DEF_INDEX });
let crate_root = self.expect_module(crate_id.as_def_id());
suggestions.extend(self.lookup_import_candidates_from_module(
lookup_ident,
namespace,
Expand Down
6 changes: 3 additions & 3 deletions compiler/rustc_resolve/src/imports.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -427,7 +427,7 @@ impl<'a> Resolver<'a> {
match ident.span.glob_adjust(module.expansion, glob_import.span) {
Some(Some(def)) => {
tmp_parent_scope =
ParentScope { module: self.macro_def_scope(def), ..*parent_scope };
ParentScope { module: self.expn_def_scope(def), ..*parent_scope };
adjusted_parent_scope = &tmp_parent_scope;
}
Some(None) => {}
Expand Down Expand Up @@ -585,7 +585,7 @@ impl<'a> Resolver<'a> {
for import in module.glob_importers.borrow_mut().iter() {
let mut ident = key.ident;
let scope = match ident.span.reverse_glob_adjust(module.expansion, import.span) {
Some(Some(def)) => self.macro_def_scope(def),
Some(Some(def)) => self.expn_def_scope(def),
Some(None) => import.parent_scope.module,
None => continue,
};
Expand Down Expand Up @@ -1364,7 +1364,7 @@ impl<'a, 'b> ImportResolver<'a, 'b> {
.collect::<Vec<_>>();
for (mut key, binding) in bindings {
let scope = match key.ident.span.reverse_glob_adjust(module.expansion, import.span) {
Some(Some(def)) => self.r.macro_def_scope(def),
Some(Some(def)) => self.r.expn_def_scope(def),
Some(None) => import.parent_scope.module,
None => continue,
};
Expand Down
8 changes: 3 additions & 5 deletions compiler/rustc_resolve/src/late.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -799,9 +799,7 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
}

fn with_scope<T>(&mut self, id: NodeId, f: impl FnOnce(&mut Self) -> T) -> T {
let id = self.r.local_def_id(id);
let module = self.r.module_map.get(&id).cloned(); // clones a reference
if let Some(module) = module {
if let Some(module) = self.r.get_module(self.r.local_def_id(id).to_def_id()) {
// Move down in the graph.
let orig_module = replace(&mut self.parent_scope.module, module);
self.with_rib(ValueNS, ModuleRibKind(module), |this| {
Expand Down Expand Up @@ -1872,7 +1870,7 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
if this.should_report_errs() {
let (err, candidates) = this.smart_resolve_report_errors(path, span, source, res);

let def_id = this.parent_scope.module.nearest_parent_mod;
let def_id = this.parent_scope.module.nearest_parent_mod();
let instead = res.is_some();
let suggestion =
if res.is_none() { this.report_missing_type_error(path) } else { None };
Expand Down Expand Up @@ -1940,7 +1938,7 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {

drop(parent_err);

let def_id = this.parent_scope.module.nearest_parent_mod;
let def_id = this.parent_scope.module.nearest_parent_mod();

if this.should_report_errs() {
this.r.use_injections.push(UseError {
Expand Down
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