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resolve: Scale back unloading of speculatively loaded crates
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petrochenkov committed Feb 15, 2024
1 parent b656f51 commit c2f2714
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Showing 7 changed files with 26 additions and 18 deletions.
10 changes: 0 additions & 10 deletions compiler/rustc_metadata/src/creader.rs
Original file line number Diff line number Diff line change
Expand Up @@ -1070,16 +1070,6 @@ impl<'a, 'tcx> CrateLoader<'a, 'tcx> {
pub fn maybe_process_path_extern(&mut self, name: Symbol) -> Option<CrateNum> {
self.maybe_resolve_crate(name, CrateDepKind::Explicit, None).ok()
}

pub fn unload_unused_crates(&mut self) {
for opt_cdata in &mut self.cstore.metas {
if let Some(cdata) = opt_cdata
&& !cdata.used()
{
*opt_cdata = None;
}
}
}
}

fn global_allocator_spans(krate: &ast::Crate) -> Vec<Span> {
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10 changes: 10 additions & 0 deletions compiler/rustc_metadata/src/rmeta/decoder/cstore_impl.rs
Original file line number Diff line number Diff line change
Expand Up @@ -519,6 +519,16 @@ pub(in crate::rmeta) fn provide(providers: &mut Providers) {
tcx.untracked().cstore.freeze();
tcx.arena.alloc_from_iter(CStore::from_tcx(tcx).iter_crate_data().map(|(cnum, _)| cnum))
},
used_crates: |tcx, ()| {
// The list of loaded crates is now frozen in query cache,
// so make sure cstore is not mutably accessed from here on.
tcx.untracked().cstore.freeze();
tcx.arena.alloc_from_iter(
CStore::from_tcx(tcx)
.iter_crate_data()
.filter_map(|(cnum, data)| data.used().then_some(cnum)),
)
},
..providers.queries
};
provide_extern(&mut providers.extern_queries);
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7 changes: 7 additions & 0 deletions compiler/rustc_middle/src/query/mod.rs
Original file line number Diff line number Diff line change
Expand Up @@ -1872,6 +1872,13 @@ rustc_queries! {
eval_always
desc { "fetching all foreign CrateNum instances" }
}
// Crates that are loaded non-speculatively (not for diagnostics or doc links).
// FIXME: This is currently only used for collecting lang items, but should be used instead of
// `crates` in most other cases too.
query used_crates(_: ()) -> &'tcx [CrateNum] {
eval_always
desc { "fetching `CrateNum`s for all crates loaded non-speculatively" }
}

/// A list of all traits in a crate, used by rustdoc and error reporting.
query traits(_: CrateNum) -> &'tcx [DefId] {
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2 changes: 1 addition & 1 deletion compiler/rustc_passes/src/lang_items.rs
Original file line number Diff line number Diff line change
Expand Up @@ -250,7 +250,7 @@ fn get_lang_items(tcx: TyCtxt<'_>, (): ()) -> LanguageItems {
let mut collector = LanguageItemCollector::new(tcx, resolver);

// Collect lang items in other crates.
for &cnum in tcx.crates(()).iter() {
for &cnum in tcx.used_crates(()).iter() {
for &(def_id, lang_item) in tcx.defined_lang_items(cnum).iter() {
collector.collect_item(lang_item, def_id, None);
}
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5 changes: 0 additions & 5 deletions compiler/rustc_resolve/src/late.rs
Original file line number Diff line number Diff line change
Expand Up @@ -23,7 +23,6 @@ use rustc_hir::def::Namespace::{self, *};
use rustc_hir::def::{self, CtorKind, DefKind, LifetimeRes, NonMacroAttrKind, PartialRes, PerNS};
use rustc_hir::def_id::{DefId, LocalDefId, CRATE_DEF_ID, LOCAL_CRATE};
use rustc_hir::{BindingAnnotation, PrimTy, TraitCandidate};
use rustc_metadata::creader::CStore;
use rustc_middle::middle::resolve_bound_vars::Set1;
use rustc_middle::{bug, span_bug};
use rustc_session::config::{CrateType, ResolveDocLinks};
Expand Down Expand Up @@ -4557,10 +4556,6 @@ impl<'a: 'ast, 'b, 'ast, 'tcx> LateResolutionVisitor<'a, 'b, 'ast, 'tcx> {
// Encoding foreign def ids in proc macro crate metadata will ICE.
return None;
}
// Doc paths should be resolved speculatively and should not produce any
// diagnostics, but if they are indeed resolved, then we need to keep the
// corresponding crate alive.
CStore::from_tcx_mut(self.r.tcx).set_used_recursively(def_id.krate);
}
res
});
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1 change: 0 additions & 1 deletion compiler/rustc_resolve/src/lib.rs
Original file line number Diff line number Diff line change
Expand Up @@ -1634,7 +1634,6 @@ impl<'a, 'tcx> Resolver<'a, 'tcx> {
self.tcx
.sess
.time("resolve_postprocess", || self.crate_loader(|c| c.postprocess(krate)));
self.crate_loader(|c| c.unload_unused_crates());
});

// Make sure we don't mutate the cstore from here on.
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9 changes: 8 additions & 1 deletion tests/ui/extern-flag/empty-extern-arg.stderr
Original file line number Diff line number Diff line change
@@ -1,6 +1,13 @@
error: extern location for std does not exist:

error: `#[panic_handler]` function required, but not found

error: unwinding panics are not supported without std
|
= help: using nightly cargo, use -Zbuild-std with panic="abort" to avoid unwinding
= note: since the core library is usually precompiled with panic="unwind", rebuilding your crate with panic="abort" may not be enough to fix the problem

error: requires `sized` lang_item

error: aborting due to 2 previous errors
error: aborting due to 4 previous errors

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