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rustc_metadata: Make opt_item_ident in decoder faster and stricter

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By avoiding formatting and allocations in the no-ident case, and by making the span mandatory if the ident exists.

Use the optimized `opt_item_ident` to cleanup `fn each_child_of_item`
This commit is contained in:
Vadim Petrochenkov 2022-01-06 12:23:01 +08:00
parent 4c6120c386
commit 4e8855bdc9
2 changed files with 25 additions and 36 deletions
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57
compiler/rustc_metadata/src/rmeta/decoder.rs
View File

@ -722,25 +722,24 @@ impl<'a, 'tcx> CrateMetadataRef<'a> {
&self.raw_proc_macros.unwrap()[pos]
}
fn try_item_ident(&self, item_index: DefIndex, sess: &Session) -> Result<Ident, String> {
let name = self
.def_key(item_index)
.disambiguated_data
.data
.get_opt_name()
.ok_or_else(|| format!("Missing opt name for {:?}", item_index))?;
let span = self
.root
.tables
.ident_span
.get(self, item_index)
.ok_or_else(|| format!("Missing ident span for {:?} ({:?})", name, item_index))?
.decode((self, sess));
Ok(Ident::new(name, span))
fn opt_item_ident(&self, item_index: DefIndex, sess: &Session) -> Option<Ident> {
let name = self.def_key(item_index).disambiguated_data.data.get_opt_name()?;
let span = match self.root.tables.ident_span.get(self, item_index) {
Some(lazy_span) => lazy_span.decode((self, sess)),
None => {
// FIXME: this weird case of a name with no span is specific to `extern crate`
// items, which are supposed to be treated like `use` items and only be encoded
// to metadata as `Export`s, return `None` because that's what all the callers
// expect in this case.
assert_eq!(self.def_kind(item_index), DefKind::ExternCrate);
return None;
}
};
Some(Ident::new(name, span))
}
fn item_ident(&self, item_index: DefIndex, sess: &Session) -> Ident {
self.try_item_ident(item_index, sess).unwrap()
self.opt_item_ident(item_index, sess).expect("no encoded ident for item")
}
fn maybe_kind(&self, item_id: DefIndex) -> Option<EntryKind> {
@ -1102,27 +1101,19 @@ impl<'a, 'tcx> CrateMetadataRef<'a> {
// Iterate over all children.
if let Some(children) = self.root.tables.children.get(self, id) {
for child_index in children.decode((self, sess)) {
// FIXME: Merge with the logic below.
if let None | Some(EntryKind::ForeignMod | EntryKind::Impl(_)) =
self.maybe_kind(child_index)
{
continue;
}
let def_key = self.def_key(child_index);
if def_key.disambiguated_data.data.get_opt_name().is_some() {
let span = self.get_span(child_index, sess);
if let Some(ident) = self.opt_item_ident(child_index, sess) {
let kind = self.def_kind(child_index);
let ident = self.item_ident(child_index, sess);
let vis = self.get_visibility(child_index);
if matches!(kind, DefKind::Macro(..)) {
// FIXME: Macros are currently encoded twice, once as items and once as
// reexports. We ignore the items here and only use the reexports.
continue;
}
let def_id = self.local_def_id(child_index);
let res = Res::Def(kind, def_id);
let vis = self.get_visibility(child_index);
let span = self.get_span(child_index, sess);
// FIXME: Macros are currently encoded twice, once as items and once as
// reexports. We ignore the items here and only use the reexports.
if !matches!(kind, DefKind::Macro(..)) {
callback(Export { res, ident, vis, span });
}
callback(Export { ident, res, vis, span });
// For non-re-export structs and variants add their constructors to children.
// Re-export lists automatically contain constructors when necessary.

4
compiler/rustc_metadata/src/rmeta/decoder/cstore_impl.rs
View File

@ -133,9 +133,7 @@ provide! { <'tcx> tcx, def_id, other, cdata,
generator_kind => { cdata.generator_kind(def_id.index) }
opt_def_kind => { Some(cdata.def_kind(def_id.index)) }
def_span => { cdata.get_span(def_id.index, &tcx.sess) }
def_ident_span => {
cdata.try_item_ident(def_id.index, &tcx.sess).ok().map(|ident| ident.span)
}
def_ident_span => { cdata.opt_item_ident(def_id.index, &tcx.sess).map(|ident| ident.span) }
lookup_stability => {
cdata.get_stability(def_id.index).map(|s| tcx.intern_stability(s))
}