bjoernager/rust
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Revert "Rollup merge of #125572 - mu001999-contrib:dead/enhance, r=pnkfelix"

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This reverts commit 13314df21b, reversing
changes made to 6e534c73c3.
This commit is contained in:
Michael Goulet 2024-07-30 12:29:20 -04:00
parent d29818c9f5
commit ac56007ea7
32 changed files with 89 additions and 273 deletions
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121
compiler/rustc_passes/src/dead.rs
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@ -17,7 +17,7 @@ use rustc_hir::{Node, PatKind, TyKind};
use rustc_middle::middle::codegen_fn_attrs::CodegenFnAttrFlags;
use rustc_middle::middle::privacy::Level;
use rustc_middle::query::Providers;
use rustc_middle::ty::{self, AssocItemContainer, TyCtxt};
use rustc_middle::ty::{self, TyCtxt};
use rustc_middle::{bug, span_bug};
use rustc_session::lint;
use rustc_session::lint::builtin::DEAD_CODE;
@ -44,63 +44,16 @@ fn should_explore(tcx: TyCtxt<'_>, def_id: LocalDefId) -> bool {
)
}
struct Publicness {
ty_is_public: bool,
ty_and_all_fields_are_public: bool,
}
impl Publicness {
fn new(ty_is_public: bool, ty_and_all_fields_are_public: bool) -> Self {
Self { ty_is_public, ty_and_all_fields_are_public }
}
}
fn struct_all_fields_are_public(tcx: TyCtxt<'_>, id: DefId) -> bool {
// treat PhantomData and positional ZST as public,
// we don't want to lint types which only have them,
// cause it's a common way to use such types to check things like well-formedness
tcx.adt_def(id).all_fields().all(|field| {
let field_type = tcx.type_of(field.did).instantiate_identity();
if field_type.is_phantom_data() {
return true;
}
let is_positional = field.name.as_str().starts_with(|c: char| c.is_ascii_digit());
if is_positional
&& tcx
.layout_of(tcx.param_env(field.did).and(field_type))
.map_or(true, |layout| layout.is_zst())
{
return true;
}
field.vis.is_public()
})
}
/// check struct and its fields are public or not,
/// for enum and union, just check they are public,
/// and doesn't solve types like &T for now, just skip them
fn ty_ref_to_pub_struct(tcx: TyCtxt<'_>, ty: &hir::Ty<'_>) -> Publicness {
fn ty_ref_to_pub_struct(tcx: TyCtxt<'_>, ty: &hir::Ty<'_>) -> bool {
if let TyKind::Path(hir::QPath::Resolved(_, path)) = ty.kind
&& let Res::Def(def_kind, def_id) = path.res
&& def_id.is_local()
&& matches!(def_kind, DefKind::Struct | DefKind::Enum | DefKind::Union)
{
return match def_kind {
DefKind::Enum | DefKind::Union => {
let ty_is_public = tcx.visibility(def_id).is_public();
Publicness::new(ty_is_public, ty_is_public)
}
DefKind::Struct => {
let ty_is_public = tcx.visibility(def_id).is_public();
Publicness::new(
ty_is_public,
ty_is_public && struct_all_fields_are_public(tcx, def_id),
)
}
_ => Publicness::new(true, true),
};
tcx.visibility(def_id).is_public()
} else {
true
}
Publicness::new(true, true)
}
/// Determine if a work from the worklist is coming from a `#[allow]`
@ -499,11 +452,9 @@ impl<'tcx> MarkSymbolVisitor<'tcx> {
{
if !matches!(trait_item.kind, hir::TraitItemKind::Type(..))
&& !ty_ref_to_pub_struct(self.tcx, impl_ref.self_ty)
.ty_and_all_fields_are_public
{
// skip impl-items of non pure pub ty,
// cause we don't know the ty is constructed or not,
// check these later in `solve_rest_impl_items`
// skip methods of private ty,
// they would be solved in `solve_rest_impl_items`
continue;
}
@ -584,21 +535,22 @@ impl<'tcx> MarkSymbolVisitor<'tcx> {
&& let Some(local_def_id) = def_id.as_local()
&& matches!(def_kind, DefKind::Struct | DefKind::Enum | DefKind::Union)
{
if self.tcx.visibility(impl_item_id).is_public() {
// for the public method, we don't know the trait item is used or not,
// so we mark the method live if the self is used
return self.live_symbols.contains(&local_def_id);
}
if let Some(trait_item_id) = self.tcx.associated_item(impl_item_id).trait_item_def_id
&& let Some(local_id) = trait_item_id.as_local()
{
// for the local impl item, we can know the trait item is used or not,
// for the private method, we can know the trait item is used or not,
// so we mark the method live if the self is used and the trait item is used
self.live_symbols.contains(&local_id) && self.live_symbols.contains(&local_def_id)
} else {
// for the foreign method and inherent pub method,
// we don't know the trait item or the method is used or not,
// so we mark the method live if the self is used
self.live_symbols.contains(&local_def_id)
return self.live_symbols.contains(&local_id)
&& self.live_symbols.contains(&local_def_id);
}
} else {
false
}
false
}
}
@ -820,9 +772,7 @@ fn check_item<'tcx>(
.iter()
.filter_map(|def_id| def_id.as_local());
let self_ty = tcx.hir().item(id).expect_impl().self_ty;
let Publicness { ty_is_public, ty_and_all_fields_are_public } =
ty_ref_to_pub_struct(tcx, self_ty);
let ty_is_pub = ty_ref_to_pub_struct(tcx, tcx.hir().item(id).expect_impl().self_ty);
// And we access the Map here to get HirId from LocalDefId
for local_def_id in local_def_ids {
@ -838,20 +788,18 @@ fn check_item<'tcx>(
// for trait impl blocks,
// mark the method live if the self_ty is public,
// or the method is public and may construct self
if of_trait && matches!(tcx.def_kind(local_def_id), DefKind::AssocTy)
|| tcx.visibility(local_def_id).is_public()
&& (ty_and_all_fields_are_public || may_construct_self)
if of_trait
&& (!matches!(tcx.def_kind(local_def_id), DefKind::AssocFn)
|| tcx.visibility(local_def_id).is_public()
&& (ty_is_pub || may_construct_self))
{
// if the impl item is public,
// and the ty may be constructed or can be constructed in foreign crates,
// mark the impl item live
worklist.push((local_def_id, ComesFromAllowExpect::No));
} else if let Some(comes_from_allow) =
has_allow_dead_code_or_lang_attr(tcx, local_def_id)
{
worklist.push((local_def_id, comes_from_allow));
} else if of_trait || tcx.visibility(local_def_id).is_public() && ty_is_public {
// private impl items of traits || public impl items not constructs self
} else if of_trait {
// private method || public method not constructs self
unsolved_impl_items.push((id, local_def_id));
}
}
@ -918,14 +866,6 @@ fn create_and_seed_worklist(
effective_vis
.is_public_at_level(Level::Reachable)
.then_some(id)
.filter(|&id|
// checks impls, impl-items and pub structs with all public fields later
match tcx.def_kind(id) {
DefKind::Impl { .. } => false,
DefKind::AssocConst | DefKind::AssocFn => !matches!(tcx.associated_item(id).container, AssocItemContainer::ImplContainer),
DefKind::Struct => struct_all_fields_are_public(tcx, id.to_def_id()),
_ => true
})
.map(|id| (id, ComesFromAllowExpect::No))
})
// Seed entry point
@ -1250,15 +1190,10 @@ fn check_mod_deathness(tcx: TyCtxt<'_>, module: LocalModDefId) {
|| (def_kind == DefKind::Trait && live_symbols.contains(&item.owner_id.def_id))
{
for &def_id in tcx.associated_item_def_ids(item.owner_id.def_id) {
// We have diagnosed unused assoc consts and fns in traits
// We have diagnosed unused methods in traits
if matches!(def_kind, DefKind::Impl { of_trait: true })
&& matches!(tcx.def_kind(def_id), DefKind::AssocConst | DefKind::AssocFn)
// skip unused public inherent methods,
// cause we have diagnosed unconstructed struct
|| matches!(def_kind, DefKind::Impl { of_trait: false })
&& tcx.visibility(def_id).is_public()
&& ty_ref_to_pub_struct(tcx, tcx.hir().item(item).expect_impl().self_ty).ty_is_public
|| def_kind == DefKind::Trait && tcx.def_kind(def_id) == DefKind::AssocTy
&& tcx.def_kind(def_id) == DefKind::AssocFn
|| def_kind == DefKind::Trait && tcx.def_kind(def_id) != DefKind::AssocFn
{
continue;
}