Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom

Remove generics_def_id_map from the resolver. #101447

Merged
merged 1 commit into from
Sep 6, 2022
Merged

Remove generics_def_id_map from the resolver. #101447

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
1 change: 1 addition & 0 deletions compiler/rustc_ast_lowering/src/item.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -85,6 +85,7 @@ impl<'a, 'hir> ItemLowerer<'a, 'hir> {
allow_try_trait: Some([sym::try_trait_v2, sym::yeet_desugar_details][..].into()),
allow_gen_future: Some([sym::gen_future][..].into()),
allow_into_future: Some([sym::into_future][..].into()),
generics_def_id_map: Default::default(),
};
lctx.with_hir_id_owner(owner, |lctx| f(lctx));

Expand Down
83 changes: 38 additions & 45 deletions compiler/rustc_ast_lowering/src/lib.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -132,6 +132,12 @@ struct LoweringContext<'a, 'hir> {
allow_try_trait: Option<Lrc<[Symbol]>>,
allow_gen_future: Option<Lrc<[Symbol]>>,
allow_into_future: Option<Lrc<[Symbol]>>,

/// Mapping from generics `def_id`s to TAIT generics `def_id`s.
/// For each captured lifetime (e.g., 'a), we create a new lifetime parameter that is a generic
/// defined on the TAIT, so we have type Foo<'a1> = ... and we establish a mapping in this
/// field from the original parameter 'a to the new parameter 'a1.
generics_def_id_map: Vec<FxHashMap<LocalDefId, LocalDefId>>,
}

trait ResolverAstLoweringExt {
Expand All @@ -142,12 +148,6 @@ trait ResolverAstLoweringExt {
fn get_lifetime_res(&self, id: NodeId) -> Option<LifetimeRes>;
fn take_extra_lifetime_params(&mut self, id: NodeId) -> Vec<(Ident, NodeId, LifetimeRes)>;
fn decl_macro_kind(&self, def_id: LocalDefId) -> MacroKind;
/// Record the map from `from` local def id to `to` local def id, on `generics_def_id_map`
/// field.
fn record_def_id_remap(&mut self, from: LocalDefId, to: LocalDefId);
/// Get the previously recorded `to` local def id given the `from` local def id, obtained using
/// `generics_def_id_map` field.
fn get_remapped_def_id(&self, local_def_id: LocalDefId) -> LocalDefId;
}

impl ResolverAstLoweringExt for ResolverAstLowering {
Expand Down Expand Up @@ -215,41 +215,6 @@ impl ResolverAstLoweringExt for ResolverAstLowering {
fn decl_macro_kind(&self, def_id: LocalDefId) -> MacroKind {
self.builtin_macro_kinds.get(&def_id).copied().unwrap_or(MacroKind::Bang)
}

/// Push a remapping into the top-most map.
/// Panics if no map has been pushed.
/// Remapping is used when creating lowering `-> impl Trait` return
/// types to create the resulting opaque type.
#[instrument(level = "debug", skip(self))]
fn record_def_id_remap(&mut self, from: LocalDefId, to: LocalDefId) {
self.generics_def_id_map.last_mut().expect("no map pushed").insert(from, to);
}

fn get_remapped_def_id(&self, mut local_def_id: LocalDefId) -> LocalDefId {
// `generics_def_id_map` is a stack of mappings. As we go deeper in impl traits nesting we
// push new mappings so we need to try first the latest mappings, hence `iter().rev()`.
//
// Consider:
//
// `fn test<'a, 'b>() -> impl Trait<&'a u8, Ty = impl Sized + 'b> {}`
//
// We would end with a generics_def_id_map like:
//
// `[[fn#'b -> impl_trait#'b], [fn#'b -> impl_sized#'b]]`
//
// for the opaque type generated on `impl Sized + 'b`, We want the result to be:
// impl_sized#'b, so iterating forward is the wrong thing to do.
for map in self.generics_def_id_map.iter().rev() {
if let Some(r) = map.get(&local_def_id) {
debug!("def_id_remapper: remapping from `{local_def_id:?}` to `{r:?}`");
local_def_id = *r;
} else {
debug!("def_id_remapper: no remapping for `{local_def_id:?}` found in map");
}
}

local_def_id
}
}

/// Context of `impl Trait` in code, which determines whether it is allowed in an HIR subtree,
Expand Down Expand Up @@ -522,13 +487,41 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
self.resolver
.node_id_to_def_id
.get(&node)
.map(|local_def_id| self.resolver.get_remapped_def_id(*local_def_id))
.map(|local_def_id| self.get_remapped_def_id(*local_def_id))
}

fn local_def_id(&self, node: NodeId) -> LocalDefId {
self.opt_local_def_id(node).unwrap_or_else(|| panic!("no entry for node id: `{:?}`", node))
}

/// Get the previously recorded `to` local def id given the `from` local def id, obtained using
/// `generics_def_id_map` field.
fn get_remapped_def_id(&self, mut local_def_id: LocalDefId) -> LocalDefId {
// `generics_def_id_map` is a stack of mappings. As we go deeper in impl traits nesting we
// push new mappings so we need to try first the latest mappings, hence `iter().rev()`.
//
// Consider:
//
// `fn test<'a, 'b>() -> impl Trait<&'a u8, Ty = impl Sized + 'b> {}`
//
// We would end with a generics_def_id_map like:
//
// `[[fn#'b -> impl_trait#'b], [fn#'b -> impl_sized#'b]]`
//
// for the opaque type generated on `impl Sized + 'b`, We want the result to be:
// impl_sized#'b, so iterating forward is the wrong thing to do.
for map in self.generics_def_id_map.iter().rev() {
if let Some(r) = map.get(&local_def_id) {
debug!("def_id_remapper: remapping from `{local_def_id:?}` to `{r:?}`");
local_def_id = *r;
} else {
debug!("def_id_remapper: no remapping for `{local_def_id:?}` found in map");
}
}

local_def_id
}

/// Freshen the `LoweringContext` and ready it to lower a nested item.
/// The lowered item is registered into `self.children`.
///
Expand Down Expand Up @@ -597,9 +590,9 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
remap: FxHashMap<LocalDefId, LocalDefId>,
f: impl FnOnce(&mut Self) -> R,
) -> R {
self.resolver.generics_def_id_map.push(remap);
self.generics_def_id_map.push(remap);
let res = f(self);
self.resolver.generics_def_id_map.pop();
self.generics_def_id_map.pop();
res
}

Expand Down Expand Up @@ -2024,7 +2017,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
let name = match res {
LifetimeRes::Param { param, .. } => {
let p_name = ParamName::Plain(ident);
let param = self.resolver.get_remapped_def_id(param);
let param = self.get_remapped_def_id(param);

hir::LifetimeName::Param(param, p_name)
}
Expand Down
5 changes: 0 additions & 5 deletions compiler/rustc_middle/src/ty/mod.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -178,11 +178,6 @@ pub struct ResolverAstLowering {
pub label_res_map: NodeMap<ast::NodeId>,
/// Resolutions for lifetimes.
pub lifetimes_res_map: NodeMap<LifetimeRes>,
/// Mapping from generics `def_id`s to TAIT generics `def_id`s.
/// For each captured lifetime (e.g., 'a), we create a new lifetime parameter that is a generic
/// defined on the TAIT, so we have type Foo<'a1> = ... and we establish a mapping in this
/// field from the original parameter 'a to the new parameter 'a1.
pub generics_def_id_map: Vec<FxHashMap<LocalDefId, LocalDefId>>,
/// Lifetime parameters that lowering will have to introduce.
pub extra_lifetime_params_map: NodeMap<Vec<(Ident, ast::NodeId, LifetimeRes)>>,

Expand Down
8 changes: 0 additions & 8 deletions compiler/rustc_resolve/src/lib.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -911,11 +911,6 @@ pub struct Resolver<'a> {
label_res_map: NodeMap<NodeId>,
/// Resolutions for lifetimes.
lifetimes_res_map: NodeMap<LifetimeRes>,
/// Mapping from generics `def_id`s to TAIT generics `def_id`s.
/// For each captured lifetime (e.g., 'a), we create a new lifetime parameter that is a generic
/// defined on the TAIT, so we have type Foo<'a1> = ... and we establish a mapping in this
/// field from the original parameter 'a to the new parameter 'a1.
generics_def_id_map: Vec<FxHashMap<LocalDefId, LocalDefId>>,
/// Lifetime parameters that lowering will have to introduce.
extra_lifetime_params_map: NodeMap<Vec<(Ident, NodeId, LifetimeRes)>>,

Expand Down Expand Up @@ -1278,7 +1273,6 @@ impl<'a> Resolver<'a> {
import_res_map: Default::default(),
label_res_map: Default::default(),
lifetimes_res_map: Default::default(),
generics_def_id_map: Vec::new(),
extra_lifetime_params_map: Default::default(),
extern_crate_map: Default::default(),
reexport_map: FxHashMap::default(),
Expand Down Expand Up @@ -1445,7 +1439,6 @@ impl<'a> Resolver<'a> {
import_res_map: self.import_res_map,
label_res_map: self.label_res_map,
lifetimes_res_map: self.lifetimes_res_map,
generics_def_id_map: self.generics_def_id_map,
extra_lifetime_params_map: self.extra_lifetime_params_map,
next_node_id: self.next_node_id,
node_id_to_def_id: self.node_id_to_def_id,
Expand Down Expand Up @@ -1490,7 +1483,6 @@ impl<'a> Resolver<'a> {
import_res_map: self.import_res_map.clone(),
label_res_map: self.label_res_map.clone(),
lifetimes_res_map: self.lifetimes_res_map.clone(),
generics_def_id_map: self.generics_def_id_map.clone(),
extra_lifetime_params_map: self.extra_lifetime_params_map.clone(),
next_node_id: self.next_node_id.clone(),
node_id_to_def_id: self.node_id_to_def_id.clone(),
Expand Down