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Do not compute entry parent when not required.
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@cjgillot
cjgillot committed Apr 29, 2021
1 parent 2d341e1 commit 99d3798
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Showing 3 changed files with 127 additions and 100 deletions.
9 changes: 8 additions & 1 deletion compiler/rustc_middle/src/hir/map/collector.rs
View file
@@ -1,5 +1,5 @@
use crate::arena::Arena;
use crate::hir::map::{Entry, HirOwnerData, Map};
use crate::hir::map::{HirOwnerData, Map};
use crate::hir::{Owner, OwnerNodes, ParentedNode};
use crate::ich::StableHashingContext;
use rustc_data_structures::fingerprint::Fingerprint;
Expand Down Expand Up @@ -61,6 +61,13 @@ fn hash_body(
stable_hasher.finish()
}

/// Represents an entry and its parent `HirId`.
#[derive(Copy, Clone, Debug)]
pub struct Entry<'hir> {
parent: HirId,
node: Node<'hir>,
}

impl<'a, 'hir> NodeCollector<'a, 'hir> {
pub(super) fn root(
sess: &'a Session,
Expand Down
214 changes: 117 additions & 97 deletions compiler/rustc_middle/src/hir/map/mod.rs
View file
Expand Up @@ -14,6 +14,7 @@ use rustc_hir::intravisit;
use rustc_hir::intravisit::Visitor;
use rustc_hir::itemlikevisit::ItemLikeVisitor;
use rustc_hir::*;
use rustc_index::vec::Idx;
use rustc_span::hygiene::MacroKind;
use rustc_span::source_map::Spanned;
use rustc_span::symbol::{kw, Ident, Symbol};
Expand All @@ -23,13 +24,6 @@ use rustc_target::spec::abi::Abi;
pub mod blocks;
mod collector;

/// Represents an entry and its parent `HirId`.
#[derive(Copy, Clone, Debug)]
pub struct Entry<'hir> {
parent: HirId,
node: Node<'hir>,
}

fn fn_decl<'hir>(node: Node<'hir>) -> Option<&'hir FnDecl<'hir>> {
match node {
Node::Item(Item { kind: ItemKind::Fn(sig, _, _), .. })
Expand Down Expand Up @@ -108,10 +102,48 @@ impl<'hir> Iterator for ParentHirIterator<'_, 'hir> {
}

self.current_id = parent_id;
if let Some(entry) = self.map.find_entry(parent_id) {
return Some((parent_id, entry.node));
if let Some(node) = self.map.find(parent_id) {
return Some((parent_id, node));
}
// If this `HirId` doesn't have an entry, skip it and look for its `parent_id`.
}
}
}

/// An iterator that walks up the ancestor tree of a given `HirId`.
/// Constructed using `tcx.hir().parent_owner_iter(hir_id)`.
pub struct ParentOwnerIterator<'map, 'hir> {
current_id: HirId,
map: &'map Map<'hir>,
}

impl<'hir> Iterator for ParentOwnerIterator<'_, 'hir> {
type Item = (HirId, Node<'hir>);

fn next(&mut self) -> Option<Self::Item> {
if self.current_id.local_id.index() != 0 {
self.current_id.local_id = ItemLocalId::new(0);
if let Some(node) = self.map.find(self.current_id) {
return Some((self.current_id, node));
}
}
if self.current_id == CRATE_HIR_ID {
return None;
}
loop {
// There are nodes that do not have entries, so we need to skip them.
let parent_id = self.map.def_key(self.current_id.owner).parent;

let parent_id = parent_id.map_or(CRATE_HIR_ID.owner, |local_def_index| {
let def_id = LocalDefId { local_def_index };
self.map.local_def_id_to_hir_id(def_id).owner
});
self.current_id = HirId::make_owner(parent_id);

// If this `HirId` doesn't have an entry, skip it and look for its `parent_id`.
if let Some(node) = self.map.find(self.current_id) {
return Some((self.current_id, node));
}
// If this `HirId` doesn't have an `Entry`, skip it and look for its `parent_id`.
}
}
}
Expand Down Expand Up @@ -144,7 +176,7 @@ impl<'hir> Map<'hir> {
bug!(
"local_def_id: no entry for `{:?}`, which has a map of `{:?}`",
hir_id,
self.find_entry(hir_id)
self.find(hir_id)
)
})
}
Expand Down Expand Up @@ -251,27 +283,61 @@ impl<'hir> Map<'hir> {
.unwrap_or_else(|| bug!("def_kind: unsupported node: {:?}", local_def_id))
}

fn find_entry(&self, id: HirId) -> Option<Entry<'hir>> {
pub fn find_parent_node(&self, id: HirId) -> Option<HirId> {
if id.local_id == ItemLocalId::from_u32(0) {
let owner = self.tcx.hir_owner(id.owner);
owner.map(|owner| Entry { parent: owner.parent, node: owner.node })
let owner = self.tcx.hir_owner(id.owner)?;
Some(owner.parent)
} else {
let owner = self.tcx.hir_owner_nodes(id.owner);
owner.and_then(|owner| {
let node = owner.nodes[id.local_id].as_ref();
// FIXME(eddyb) use a single generic type instead of having both
// `Entry` and `ParentedNode`, which are effectively the same.
// Alternatively, rewrite code using `Entry` to use `ParentedNode`.
node.map(|node| Entry {
parent: HirId { owner: id.owner, local_id: node.parent },
node: node.node,
})
})
let owner = self.tcx.hir_owner_nodes(id.owner)?;
let node = owner.nodes[id.local_id].as_ref()?;
let hir_id = HirId { owner: id.owner, local_id: node.parent };
Some(hir_id)
}
}

fn get_entry(&self, id: HirId) -> Entry<'hir> {
self.find_entry(id).unwrap()
pub fn get_parent_node(&self, hir_id: HirId) -> HirId {
self.find_parent_node(hir_id).unwrap()
}

/// Retrieves the `Node` corresponding to `id`, returning `None` if cannot be found.
pub fn find(&self, id: HirId) -> Option<Node<'hir>> {
if id.local_id == ItemLocalId::from_u32(0) {
let owner = self.tcx.hir_owner(id.owner)?;
Some(owner.node)
} else {
let owner = self.tcx.hir_owner_nodes(id.owner)?;
let node = owner.nodes[id.local_id].as_ref()?;
Some(node.node)
}
}

/// Retrieves the `Node` corresponding to `id`, panicking if it cannot be found.
pub fn get(&self, id: HirId) -> Node<'hir> {
self.find(id).unwrap_or_else(|| bug!("couldn't find hir id {} in the HIR map", id))
}

pub fn get_if_local(&self, id: DefId) -> Option<Node<'hir>> {
id.as_local().and_then(|id| self.find(self.local_def_id_to_hir_id(id)))
}

pub fn get_generics(&self, id: DefId) -> Option<&'hir Generics<'hir>> {
self.get_if_local(id).and_then(|node| match &node {
Node::ImplItem(impl_item) => Some(&impl_item.generics),
Node::TraitItem(trait_item) => Some(&trait_item.generics),
Node::Item(Item {
kind:
ItemKind::Fn(_, generics, _)
| ItemKind::TyAlias(_, generics)
| ItemKind::Enum(_, generics)
| ItemKind::Struct(_, generics)
| ItemKind::Union(_, generics)
| ItemKind::Trait(_, _, generics, ..)
| ItemKind::TraitAlias(generics, _)
| ItemKind::Impl(Impl { generics, .. }),
..
}) => Some(generics),
_ => None,
})
}

pub fn item(&self, id: ItemId) -> &'hir Item<'hir> {
Expand Down Expand Up @@ -436,7 +502,7 @@ impl<'hir> Map<'hir> {

pub fn get_module(&self, module: LocalDefId) -> (&'hir Mod<'hir>, Span, HirId) {
let hir_id = self.local_def_id_to_hir_id(module);
match self.get_entry(hir_id).node {
match self.get(hir_id) {
Node::Item(&Item { span, kind: ItemKind::Mod(ref m), .. }) => (m, span, hir_id),
Node::Crate(item) => (&item, item.inner, hir_id),
node => panic!("not a module: {:?}", node),
Expand Down Expand Up @@ -475,60 +541,18 @@ impl<'hir> Map<'hir> {
}
}

/// Retrieves the `Node` corresponding to `id`, panicking if it cannot be found.
pub fn get(&self, id: HirId) -> Node<'hir> {
self.find(id).unwrap_or_else(|| bug!("couldn't find hir id {} in the HIR map", id))
}

pub fn get_if_local(&self, id: DefId) -> Option<Node<'hir>> {
id.as_local().and_then(|id| self.find(self.local_def_id_to_hir_id(id)))
}

pub fn get_generics(&self, id: DefId) -> Option<&'hir Generics<'hir>> {
self.get_if_local(id).and_then(|node| match &node {
Node::ImplItem(impl_item) => Some(&impl_item.generics),
Node::TraitItem(trait_item) => Some(&trait_item.generics),
Node::Item(Item {
kind:
ItemKind::Fn(_, generics, _)
| ItemKind::TyAlias(_, generics)
| ItemKind::Enum(_, generics)
| ItemKind::Struct(_, generics)
| ItemKind::Union(_, generics)
| ItemKind::Trait(_, _, generics, ..)
| ItemKind::TraitAlias(generics, _)
| ItemKind::Impl(Impl { generics, .. }),
..
}) => Some(generics),
_ => None,
})
}

/// Retrieves the `Node` corresponding to `id`, returning `None` if cannot be found.
pub fn find(&self, hir_id: HirId) -> Option<Node<'hir>> {
self.find_entry(hir_id).map(|entry| entry.node)
}

/// Similar to `get_parent`; returns the parent HIR Id, or just `hir_id` if there
/// is no parent. Note that the parent may be `CRATE_HIR_ID`, which is not itself
/// present in the map, so passing the return value of `get_parent_node` to
/// `get` may in fact panic.
/// This function returns the immediate parent in the HIR, whereas `get_parent`
/// returns the enclosing item. Note that this might not be the actual parent
/// node in the HIR -- some kinds of nodes are not in the map and these will
/// never appear as the parent node. Thus, you can always walk the parent nodes
/// from a node to the root of the HIR (unless you get back the same ID here,
/// which can happen if the ID is not in the map itself or is just weird).
pub fn get_parent_node(&self, hir_id: HirId) -> HirId {
self.get_entry(hir_id).parent
}

/// Returns an iterator for the nodes in the ancestor tree of the `current_id`
/// until the crate root is reached. Prefer this over your own loop using `get_parent_node`.
pub fn parent_iter(&self, current_id: HirId) -> ParentHirIterator<'_, 'hir> {
ParentHirIterator { current_id, map: self }
}

/// Returns an iterator for the nodes in the ancestor tree of the `current_id`
/// until the crate root is reached. Prefer this over your own loop using `get_parent_node`.
pub fn parent_owner_iter(&self, current_id: HirId) -> ParentOwnerIterator<'_, 'hir> {
ParentOwnerIterator { current_id, map: self }
}

/// Checks if the node is left-hand side of an assignment.
pub fn is_lhs(&self, id: HirId) -> bool {
match self.find(self.get_parent_node(id)) {
Expand All @@ -549,7 +573,7 @@ impl<'hir> Map<'hir> {
/// Whether `hir_id` corresponds to a `mod` or a crate.
pub fn is_hir_id_module(&self, hir_id: HirId) -> bool {
matches!(
self.get_entry(hir_id).node,
self.get(hir_id),
Node::Item(Item { kind: ItemKind::Mod(_), .. }) | Node::Crate(..)
)
}
Expand Down Expand Up @@ -579,8 +603,8 @@ impl<'hir> Map<'hir> {
pub fn get_return_block(&self, id: HirId) -> Option<HirId> {
let mut iter = self.parent_iter(id).peekable();
let mut ignore_tail = false;
if let Some(entry) = self.find_entry(id) {
if let Node::Expr(Expr { kind: ExprKind::Ret(_), .. }) = entry.node {
if let Some(node) = self.find(id) {
if let Node::Expr(Expr { kind: ExprKind::Ret(_), .. }) = node {
// When dealing with `return` statements, we don't care about climbing only tail
// expressions.
ignore_tail = true;
Expand Down Expand Up @@ -617,23 +641,23 @@ impl<'hir> Map<'hir> {
/// in the HIR which is recorded by the map and is an item, either an item
/// in a module, trait, or impl.
pub fn get_parent_item(&self, hir_id: HirId) -> HirId {
for (hir_id, node) in self.parent_iter(hir_id) {
match node {
Node::Crate(_)
| Node::Item(_)
| Node::ForeignItem(_)
| Node::TraitItem(_)
| Node::ImplItem(_) => return hir_id,
_ => {}
for (hir_id, node) in self.parent_owner_iter(hir_id) {
if let Node::Crate(_)
| Node::Item(_)
| Node::ForeignItem(_)
| Node::TraitItem(_)
| Node::ImplItem(_) = node
{
return hir_id;
}
}
hir_id
CRATE_HIR_ID
}

/// Returns the `HirId` of `id`'s nearest module parent, or `id` itself if no
/// module parent is in this map.
pub(super) fn get_module_parent_node(&self, hir_id: HirId) -> HirId {
for (hir_id, node) in self.parent_iter(hir_id) {
for (hir_id, node) in self.parent_owner_iter(hir_id) {
if let Node::Item(&Item { kind: ItemKind::Mod(_), .. }) = node {
return hir_id;
}
Expand Down Expand Up @@ -707,12 +731,8 @@ impl<'hir> Map<'hir> {

pub fn get_foreign_abi(&self, hir_id: HirId) -> Abi {
let parent = self.get_parent_item(hir_id);
if let Some(entry) = self.find_entry(parent) {
if let Entry {
node: Node::Item(Item { kind: ItemKind::ForeignMod { abi, .. }, .. }),
..
} = entry
{
if let Some(node) = self.find(parent) {
if let Node::Item(Item { kind: ItemKind::ForeignMod { abi, .. }, .. }) = node {
return *abi;
}
}
Expand Down Expand Up @@ -806,7 +826,7 @@ impl<'hir> Map<'hir> {
}

pub fn opt_span(&self, hir_id: HirId) -> Option<Span> {
let span = match self.find_entry(hir_id)?.node {
let span = match self.find(hir_id)? {
Node::Param(param) => param.span,
Node::Item(item) => match &item.kind {
ItemKind::Fn(sig, _, _) => sig.span,
Expand Down Expand Up @@ -855,7 +875,7 @@ impl<'hir> Map<'hir> {
/// Like `hir.span()`, but includes the body of function items
/// (instead of just the function header)
pub fn span_with_body(&self, hir_id: HirId) -> Span {
match self.find_entry(hir_id).map(|entry| entry.node) {
match self.find(hir_id) {
Some(Node::TraitItem(item)) => item.span,
Some(Node::ImplItem(impl_item)) => impl_item.span,
Some(Node::Item(item)) => item.span,
Expand Down
4 changes: 2 additions & 2 deletions compiler/rustc_middle/src/hir/mod.rs
View file
Expand Up @@ -38,10 +38,10 @@ pub struct Owner<'tcx> {

impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for Owner<'tcx> {
fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
let Owner { parent, node } = self;
let Owner { node, parent } = self;
hcx.while_hashing_hir_bodies(false, |hcx| {
parent.hash_stable(hcx, hasher);
node.hash_stable(hcx, hasher);
node.hash_stable(hcx, hasher)
});
}
}
Expand Down

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