use rustc_data_structures::fingerprint::Fingerprint;
use rustc_data_structures::fx::FxHashMap;
use rustc_data_structures::stable_hasher::StableHasher;
-use rustc_data_structures::sync::{join, par_for_each_in, Lrc};
+use rustc_data_structures::sync::{join, Lrc};
use rustc_hir as hir;
use rustc_hir::def::CtorKind;
+use rustc_hir::def_id::DefIdSet;
use rustc_hir::def_id::{CrateNum, DefId, DefIndex, LocalDefId, CRATE_DEF_INDEX, LOCAL_CRATE};
use rustc_hir::intravisit::{self, NestedVisitorMap, Visitor};
-use rustc_hir::itemlikevisit::ItemLikeVisitor;
+use rustc_hir::itemlikevisit::{ItemLikeVisitor, ParItemLikeVisitor};
use rustc_hir::{AnonConst, GenericParamKind};
use rustc_index::vec::Idx;
use rustc_serialize::{opaque, Encodable, Encoder, SpecializedEncoder};
}
}
+/// Used to prefetch queries which will be needed later by metadata encoding.
+struct PrefetchVisitor<'tcx> {
+ tcx: TyCtxt<'tcx>,
+ mir_keys: &'tcx DefIdSet,
+}
+
+impl<'tcx> PrefetchVisitor<'tcx> {
+ fn prefetch_mir(&self, def_id: DefId) {
+ if self.mir_keys.contains(&def_id) {
+ self.tcx.optimized_mir(def_id);
+ self.tcx.promoted_mir(def_id);
+ }
+ }
+}
+
+impl<'tcx, 'v> ParItemLikeVisitor<'v> for PrefetchVisitor<'tcx> {
+ fn visit_item(&self, item: &hir::Item<'_>) {
+ let tcx = self.tcx;
+ match item.kind {
+ hir::ItemKind::Static(..) | hir::ItemKind::Const(..) => {
+ self.prefetch_mir(tcx.hir().local_def_id(item.hir_id))
+ }
+ hir::ItemKind::Fn(ref sig, ..) => {
+ let def_id = tcx.hir().local_def_id(item.hir_id);
+ let generics = tcx.generics_of(def_id);
+ let needs_inline = generics.requires_monomorphization(tcx)
+ || tcx.codegen_fn_attrs(def_id).requests_inline();
+ if needs_inline || sig.header.constness == hir::Constness::Const {
+ self.prefetch_mir(def_id)
+ }
+ }
+ _ => (),
+ }
+ }
+
+ fn visit_trait_item(&self, trait_item: &'v hir::TraitItem<'v>) {
+ self.prefetch_mir(self.tcx.hir().local_def_id(trait_item.hir_id));
+ }
+
+ fn visit_impl_item(&self, impl_item: &'v hir::ImplItem<'v>) {
+ let tcx = self.tcx;
+ match impl_item.kind {
+ hir::ImplItemKind::Const(..) => {
+ self.prefetch_mir(tcx.hir().local_def_id(impl_item.hir_id))
+ }
+ hir::ImplItemKind::Fn(ref sig, _) => {
+ let def_id = tcx.hir().local_def_id(impl_item.hir_id);
+ let generics = tcx.generics_of(def_id);
+ let needs_inline = generics.requires_monomorphization(tcx)
+ || tcx.codegen_fn_attrs(def_id).requests_inline();
+ let is_const_fn = sig.header.constness == hir::Constness::Const;
+ if needs_inline || is_const_fn {
+ self.prefetch_mir(def_id)
+ }
+ }
+ hir::ImplItemKind::OpaqueTy(..) | hir::ImplItemKind::TyAlias(..) => (),
+ }
+ }
+}
+
// NOTE(eddyb) The following comment was preserved for posterity, even
// though it's no longer relevant as EBML (which uses nested & tagged
// "documents") was replaced with a scheme that can't go out of bounds.
join(
|| encode_metadata_impl(tcx),
|| {
- // Prefetch some queries used by metadata encoding
+ if tcx.sess.threads() == 1 {
+ return;
+ }
+ // Prefetch some queries used by metadata encoding.
tcx.dep_graph.with_ignore(|| {
join(
|| {
- par_for_each_in(tcx.mir_keys(LOCAL_CRATE), |&def_id| {
- tcx.optimized_mir(def_id);
- tcx.promoted_mir(def_id);
- })
+ if !tcx.sess.opts.output_types.should_codegen() {
+ // We won't emit MIR, so don't prefetch it.
+ return;
+ }
+ tcx.hir().krate().par_visit_all_item_likes(&PrefetchVisitor {
+ tcx,
+ mir_keys: tcx.mir_keys(LOCAL_CRATE),
+ });
},
|| tcx.exported_symbols(LOCAL_CRATE),
);