bjoernager/rust
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Share inline(never) generics across crates

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This reduces code sizes and better respects programmer intent when
marking inline(never). Previously such a marking was essentially ignored
for generic functions, as we'd still inline them in remote crates.
This commit is contained in:
Mark Rousskov 2024-11-23 13:19:17 -05:00
parent 39cb3386dd
commit 4a216a25d1
26 changed files with 127 additions and 52 deletions
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32
compiler/rustc_monomorphize/src/partitioning.rs
View file

@ -208,8 +208,8 @@ where
// available to downstream crates. This depends on whether we are in
// share-generics mode and whether the current crate can even have
// downstream crates.
let export_generics =
cx.tcx.sess.opts.share_generics() && cx.tcx.local_crate_exports_generics();
let can_export_generics = cx.tcx.local_crate_exports_generics();
let always_export_generics = can_export_generics && cx.tcx.sess.opts.share_generics();
let cgu_name_builder = &mut CodegenUnitNameBuilder::new(cx.tcx);
let cgu_name_cache = &mut UnordMap::default();
@ -249,7 +249,8 @@ where
cx.tcx,
&mono_item,
&mut can_be_internalized,
export_generics,
can_export_generics,
always_export_generics,
);
if visibility == Visibility::Hidden && can_be_internalized {
internalization_candidates.insert(mono_item);
@ -739,12 +740,19 @@ fn mono_item_linkage_and_visibility<'tcx>(
tcx: TyCtxt<'tcx>,
mono_item: &MonoItem<'tcx>,
can_be_internalized: &mut bool,
export_generics: bool,
can_export_generics: bool,
always_export_generics: bool,
) -> (Linkage, Visibility) {
if let Some(explicit_linkage) = mono_item.explicit_linkage(tcx) {
return (explicit_linkage, Visibility::Default);
}
let vis = mono_item_visibility(tcx, mono_item, can_be_internalized, export_generics);
let vis = mono_item_visibility(
tcx,
mono_item,
can_be_internalized,
can_export_generics,
always_export_generics,
);
(Linkage::External, vis)
}
@ -767,7 +775,8 @@ fn mono_item_visibility<'tcx>(
tcx: TyCtxt<'tcx>,
mono_item: &MonoItem<'tcx>,
can_be_internalized: &mut bool,
export_generics: bool,
can_export_generics: bool,
always_export_generics: bool,
) -> Visibility {
let instance = match mono_item {
// This is pretty complicated; see below.
@ -826,7 +835,11 @@ fn mono_item_visibility<'tcx>(
// Upstream `DefId` instances get different handling than local ones.
let Some(def_id) = def_id.as_local() else {
return if export_generics && is_generic {
return if is_generic
&& (always_export_generics
|| (can_export_generics
&& tcx.codegen_fn_attrs(def_id).inline == rustc_attr::InlineAttr::Never))
{
// If it is an upstream monomorphization and we export generics, we must make
// it available to downstream crates.
*can_be_internalized = false;
@ -837,7 +850,10 @@ fn mono_item_visibility<'tcx>(
};
if is_generic {
if export_generics {
if always_export_generics
|| (can_export_generics
&& tcx.codegen_fn_attrs(def_id).inline == rustc_attr::InlineAttr::Never)
{
if tcx.is_unreachable_local_definition(def_id) {
// This instance cannot be used from another crate.
Visibility::Hidden