Generate metadata by iterating on DefId instead of traversing the HIR tree 1/N

compiler/rustc_hir/src/definitions.rs

@@ -419,6 +419,10 @@ impl Definitions {
     pub fn add_parent_module_of_macro_def(&mut self, expn_id: ExpnId, module: DefId) {
         self.parent_modules_of_macro_defs.insert(expn_id, module);
     }
+
+    pub fn iter_local_def_id(&self) -> impl Iterator<Item = LocalDefId> + '_ {
+        self.def_id_to_hir_id.iter_enumerated().map(|(k, _)| k)
+    }
 }
 
 #[derive(Copy, Clone, PartialEq, Debug)]

compiler/rustc_metadata/src/rmeta/decoder.rs

@@ -618,43 +618,6 @@ impl MetadataBlob {
     }
 }
 
-impl EntryKind {
-    fn def_kind(&self) -> DefKind {
-        match *self {
-            EntryKind::AnonConst(..) => DefKind::AnonConst,
-            EntryKind::Const(..) => DefKind::Const,
-            EntryKind::AssocConst(..) => DefKind::AssocConst,
-            EntryKind::ImmStatic
-            | EntryKind::MutStatic
-            | EntryKind::ForeignImmStatic
-            | EntryKind::ForeignMutStatic => DefKind::Static,
-            EntryKind::Struct(_, _) => DefKind::Struct,
-            EntryKind::Union(_, _) => DefKind::Union,
-            EntryKind::Fn(_) | EntryKind::ForeignFn(_) => DefKind::Fn,
-            EntryKind::AssocFn(_) => DefKind::AssocFn,
-            EntryKind::Type => DefKind::TyAlias,
-            EntryKind::TypeParam => DefKind::TyParam,
-            EntryKind::ConstParam => DefKind::ConstParam,
-            EntryKind::OpaqueTy => DefKind::OpaqueTy,
-            EntryKind::AssocType(_) => DefKind::AssocTy,
-            EntryKind::Mod(_) => DefKind::Mod,
-            EntryKind::Variant(_) => DefKind::Variant,
-            EntryKind::Trait(_) => DefKind::Trait,
-            EntryKind::TraitAlias => DefKind::TraitAlias,
-            EntryKind::Enum(..) => DefKind::Enum,
-            EntryKind::MacroDef(_) => DefKind::Macro(MacroKind::Bang),
-            EntryKind::ProcMacro(kind) => DefKind::Macro(kind),
-            EntryKind::ForeignType => DefKind::ForeignTy,
-            EntryKind::Impl(_) => DefKind::Impl,
-            EntryKind::Closure => DefKind::Closure,
-            EntryKind::ForeignMod => DefKind::ForeignMod,
-            EntryKind::GlobalAsm => DefKind::GlobalAsm,
-            EntryKind::Field => DefKind::Field,
-            EntryKind::Generator(_) => DefKind::Generator,
-        }
-    }
-}
-
 impl CrateRoot<'_> {
     crate fn is_proc_macro_crate(&self) -> bool {
         self.proc_macro_data.is_some()
@@ -685,21 +648,6 @@ impl CrateRoot<'_> {
 }
 
 impl<'a, 'tcx> CrateMetadataRef<'a> {
-    fn maybe_kind(&self, item_id: DefIndex) -> Option<EntryKind> {
-        self.root.tables.kind.get(self, item_id).map(|k| k.decode(self))
-    }
-
-    fn kind(&self, item_id: DefIndex) -> EntryKind {
-        self.maybe_kind(item_id).unwrap_or_else(|| {
-            bug!(
-                "CrateMetadata::kind({:?}): id not found, in crate {:?} with number {}",
-                item_id,
-                self.root.name,
-                self.cnum,
-            )
-        })
-    }
-
     fn raw_proc_macro(&self, id: DefIndex) -> &ProcMacro {
         // DefIndex's in root.proc_macro_data have a one-to-one correspondence
         // with items in 'raw_proc_macros'.
@@ -736,8 +684,30 @@ impl<'a, 'tcx> CrateMetadataRef<'a> {
         self.try_item_ident(item_index, sess).unwrap()
     }
 
-    fn def_kind(&self, index: DefIndex) -> DefKind {
-        self.kind(index).def_kind()
+    fn maybe_kind(&self, item_id: DefIndex) -> Option<EntryKind> {
+        self.root.tables.kind.get(self, item_id).map(|k| k.decode(self))
+    }
+
+    fn kind(&self, item_id: DefIndex) -> EntryKind {
+        self.maybe_kind(item_id).unwrap_or_else(|| {
+            bug!(
+                "CrateMetadata::kind({:?}): id not found, in crate {:?} with number {}",
+                item_id,
+                self.root.name,
+                self.cnum,
+            )
+        })
+    }
+
+    fn def_kind(&self, item_id: DefIndex) -> DefKind {
+        self.root.tables.def_kind.get(self, item_id).map(|k| k.decode(self)).unwrap_or_else(|| {
+            bug!(
+                "CrateMetadata::def_kind({:?}): id not found, in crate {:?} with number {}",
+                item_id,
+                self.root.name,
+                self.cnum,
+            )
+        })
     }
 
     fn get_span(&self, index: DefIndex, sess: &Session) -> Span {

compiler/rustc_metadata/src/rmeta/decoder/cstore_impl.rs

@@ -130,7 +130,7 @@ provide! { <'tcx> tcx, def_id, other, cdata,
     is_foreign_item => { cdata.is_foreign_item(def_id.index) }
     static_mutability => { cdata.static_mutability(def_id.index) }
     generator_kind => { cdata.generator_kind(def_id.index) }
-    def_kind => { cdata.def_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)

compiler/rustc_metadata/src/rmeta/mod.rs

@@ -6,7 +6,7 @@ use rustc_attr as attr;
 use rustc_data_structures::svh::Svh;
 use rustc_data_structures::sync::MetadataRef;
 use rustc_hir as hir;
-use rustc_hir::def::CtorKind;
+use rustc_hir::def::{CtorKind, DefKind};
 use rustc_hir::def_id::{DefId, DefIndex, DefPathHash};
 use rustc_hir::definitions::DefKey;
 use rustc_hir::lang_items;
@@ -279,6 +279,7 @@ macro_rules! define_tables {
 }
 
 define_tables! {
+    def_kind: Table<DefIndex, Lazy<DefKind>>,
     kind: Table<DefIndex, Lazy<EntryKind>>,
     visibility: Table<DefIndex, Lazy<ty::Visibility>>,
     span: Table<DefIndex, Lazy<Span>>,

compiler/rustc_middle/src/hir/map/mod.rs

@@ -1,7 +1,6 @@
 use self::collector::NodeCollector;
 
 use crate::hir::{Owner, OwnerNodes};
-use crate::ty::query::Providers;
 use crate::ty::TyCtxt;
 use rustc_ast as ast;
 use rustc_data_structures::svh::Svh;
@@ -183,14 +182,18 @@ impl<'hir> Map<'hir> {
         self.tcx.definitions.opt_local_def_id_to_hir_id(def_id)
     }
 
-    pub fn def_kind(&self, local_def_id: LocalDefId) -> DefKind {
+    pub fn iter_local_def_id(&self) -> impl Iterator<Item = LocalDefId> + '_ {
+        self.tcx.definitions.iter_local_def_id()
+    }
+
+    pub fn opt_def_kind(&self, local_def_id: LocalDefId) -> Option<DefKind> {
         // FIXME(eddyb) support `find` on the crate root.
         if local_def_id.to_def_id().index == CRATE_DEF_INDEX {
-            return DefKind::Mod;
+            return Some(DefKind::Mod);
         }
 
         let hir_id = self.local_def_id_to_hir_id(local_def_id);
-        match self.get(hir_id) {
+        let def_kind = match self.find(hir_id)? {
             Node::Item(item) => match item.kind {
                 ItemKind::Static(..) => DefKind::Static,
                 ItemKind::Const(..) => DefKind::Const,
@@ -249,6 +252,7 @@ impl<'hir> Map<'hir> {
                 GenericParamKind::Type { .. } => DefKind::TyParam,
                 GenericParamKind::Const { .. } => DefKind::ConstParam,
             },
+            Node::Crate(_) => DefKind::Mod,
             Node::Stmt(_)
             | Node::PathSegment(_)
             | Node::Ty(_)
@@ -260,9 +264,14 @@ impl<'hir> Map<'hir> {
             | Node::Arm(_)
             | Node::Lifetime(_)
             | Node::Visibility(_)
-            | Node::Block(_)
-            | Node::Crate(_) => bug!("def_kind: unsupported node: {}", self.node_to_string(hir_id)),
-        }
+            | Node::Block(_) => return None,
+        };
+        Some(def_kind)
+    }
+
+    pub fn def_kind(&self, local_def_id: LocalDefId) -> DefKind {
+        self.opt_def_kind(local_def_id)
+            .unwrap_or_else(|| bug!("def_kind: unsupported node: {:?}", local_def_id))
     }
 
     fn find_entry(&self, id: HirId) -> Option<Entry<'hir>> {
@@ -514,9 +523,7 @@ impl<'hir> Map<'hir> {
 
     /// Retrieves the `Node` corresponding to `id`, returning `None` if cannot be found.
     pub fn find(&self, hir_id: HirId) -> Option<Node<'hir>> {
-        self.find_entry(hir_id).and_then(|entry| {
-            if let Node::Crate(..) = entry.node { None } else { Some(entry.node) }
-        })
+        self.find_entry(hir_id).map(|entry| entry.node)
     }
 
     /// Similar to `get_parent`; returns the parent HIR Id, or just `hir_id` if there
@@ -848,50 +855,55 @@ impl<'hir> Map<'hir> {
     /// Gets the span of the definition of the specified HIR node.
     /// This is used by `tcx.get_span`
     pub fn span(&self, hir_id: HirId) -> Span {
-        match self.find_entry(hir_id).map(|entry| entry.node) {
-            Some(Node::Param(param)) => param.span,
-            Some(Node::Item(item)) => match &item.kind {
+        self.opt_span(hir_id)
+            .unwrap_or_else(|| bug!("hir::map::Map::span: id not in map: {:?}", hir_id))
+    }
+
+    pub fn opt_span(&self, hir_id: HirId) -> Option<Span> {
+        let span = match self.find_entry(hir_id)?.node {
+            Node::Param(param) => param.span,
+            Node::Item(item) => match &item.kind {
                 ItemKind::Fn(sig, _, _) => sig.span,
                 _ => item.span,
             },
-            Some(Node::ForeignItem(foreign_item)) => foreign_item.span,
-            Some(Node::TraitItem(trait_item)) => match &trait_item.kind {
+            Node::ForeignItem(foreign_item) => foreign_item.span,
+            Node::TraitItem(trait_item) => match &trait_item.kind {
                 TraitItemKind::Fn(sig, _) => sig.span,
                 _ => trait_item.span,
             },
-            Some(Node::ImplItem(impl_item)) => match &impl_item.kind {
+            Node::ImplItem(impl_item) => match &impl_item.kind {
                 ImplItemKind::Fn(sig, _) => sig.span,
                 _ => impl_item.span,
             },
-            Some(Node::Variant(variant)) => variant.span,
-            Some(Node::Field(field)) => field.span,
-            Some(Node::AnonConst(constant)) => self.body(constant.body).value.span,
-            Some(Node::Expr(expr)) => expr.span,
-            Some(Node::Stmt(stmt)) => stmt.span,
-            Some(Node::PathSegment(seg)) => seg.ident.span,
-            Some(Node::Ty(ty)) => ty.span,
-            Some(Node::TraitRef(tr)) => tr.path.span,
-            Some(Node::Binding(pat)) => pat.span,
-            Some(Node::Pat(pat)) => pat.span,
-            Some(Node::Arm(arm)) => arm.span,
-            Some(Node::Block(block)) => block.span,
-            Some(Node::Ctor(..)) => match self.find(self.get_parent_node(hir_id)) {
-                Some(Node::Item(item)) => item.span,
-                Some(Node::Variant(variant)) => variant.span,
+            Node::Variant(variant) => variant.span,
+            Node::Field(field) => field.span,
+            Node::AnonConst(constant) => self.body(constant.body).value.span,
+            Node::Expr(expr) => expr.span,
+            Node::Stmt(stmt) => stmt.span,
+            Node::PathSegment(seg) => seg.ident.span,
+            Node::Ty(ty) => ty.span,
+            Node::TraitRef(tr) => tr.path.span,
+            Node::Binding(pat) => pat.span,
+            Node::Pat(pat) => pat.span,
+            Node::Arm(arm) => arm.span,
+            Node::Block(block) => block.span,
+            Node::Ctor(..) => match self.find(self.get_parent_node(hir_id))? {
+                Node::Item(item) => item.span,
+                Node::Variant(variant) => variant.span,
                 _ => unreachable!(),
             },
-            Some(Node::Lifetime(lifetime)) => lifetime.span,
-            Some(Node::GenericParam(param)) => param.span,
-            Some(Node::Visibility(&Spanned {
+            Node::Lifetime(lifetime) => lifetime.span,
+            Node::GenericParam(param) => param.span,
+            Node::Visibility(&Spanned {
                 node: VisibilityKind::Restricted { ref path, .. },
                 ..
-            })) => path.span,
-            Some(Node::Visibility(v)) => bug!("unexpected Visibility {:?}", v),
-            Some(Node::Local(local)) => local.span,
-            Some(Node::MacroDef(macro_def)) => macro_def.span,
-            Some(Node::Crate(item)) => item.span,
-            None => bug!("hir::map::Map::span: id not in map: {:?}", hir_id),
-        }
+            }) => path.span,
+            Node::Visibility(v) => bug!("unexpected Visibility {:?}", v),
+            Node::Local(local) => local.span,
+            Node::MacroDef(macro_def) => macro_def.span,
+            Node::Crate(item) => item.span,
+        };
+        Some(span)
     }
 
     /// Like `hir.span()`, but includes the body of function items
@@ -907,7 +919,7 @@ impl<'hir> Map<'hir> {
     }
 
     pub fn span_if_local(&self, id: DefId) -> Option<Span> {
-        id.as_local().map(|id| self.span(self.local_def_id_to_hir_id(id)))
+        id.as_local().and_then(|id| self.opt_span(self.local_def_id_to_hir_id(id)))
     }
 
     pub fn res_span(&self, res: Res) -> Option<Span> {
@@ -1101,7 +1113,3 @@ fn hir_id_to_string(map: &Map<'_>, id: HirId) -> String {
         None => format!("unknown node{}", id_str),
     }
 }
-
-pub fn provide(providers: &mut Providers) {
-    providers.def_kind = |tcx, def_id| tcx.hir().def_kind(def_id.expect_local());
-}

compiler/rustc_middle/src/hir/mod.rs

@@ -15,6 +15,7 @@ use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
 use rustc_hir::def_id::{LocalDefId, LOCAL_CRATE};
 use rustc_hir::*;
 use rustc_index::vec::IndexVec;
+use rustc_span::DUMMY_SP;
 
 pub struct Owner<'tcx> {
     parent: HirId,
@@ -77,6 +78,7 @@ pub fn provide(providers: &mut Providers) {
     };
     providers.hir_owner = |tcx, id| tcx.index_hir(LOCAL_CRATE).map[id].signature;
     providers.hir_owner_nodes = |tcx, id| tcx.index_hir(LOCAL_CRATE).map[id].with_bodies.as_deref();
+    providers.def_span = |tcx, def_id| tcx.hir().span_if_local(def_id).unwrap_or(DUMMY_SP);
     providers.fn_arg_names = |tcx, id| {
         let hir = tcx.hir();
         let hir_id = hir.local_def_id_to_hir_id(id.expect_local());
@@ -92,5 +94,5 @@ pub fn provide(providers: &mut Providers) {
             span_bug!(hir.span(hir_id), "fn_arg_names: unexpected item {:?}", id);
         }
     };
-    map::provide(providers);
+    providers.opt_def_kind = |tcx, def_id| tcx.hir().opt_def_kind(def_id.expect_local());
 }

compiler/rustc_middle/src/query/mod.rs

@@ -878,7 +878,7 @@ rustc_queries! {
             cache_on_disk_if { true }
         }
 
-        query def_kind(def_id: DefId) -> DefKind {
+        query opt_def_kind(def_id: DefId) -> Option<DefKind> {
             desc { |tcx| "looking up definition kind of `{}`", tcx.def_path_str(def_id) }
         }
 

compiler/rustc_middle/src/ty/query/mod.rs

@@ -130,3 +130,19 @@ mod sealed {
 }
 
 use sealed::IntoQueryParam;
+
+impl TyCtxt<'tcx> {
+    pub fn def_kind(self, def_id: impl IntoQueryParam<DefId>) -> DefKind {
+        let def_id = def_id.into_query_param();
+        self.opt_def_kind(def_id)
+            .unwrap_or_else(|| bug!("def_kind: unsupported node: {:?}", def_id))
+    }
+}
+
+impl TyCtxtAt<'tcx> {
+    pub fn def_kind(self, def_id: impl IntoQueryParam<DefId>) -> DefKind {
+        let def_id = def_id.into_query_param();
+        self.opt_def_kind(def_id)
+            .unwrap_or_else(|| bug!("def_kind: unsupported node: {:?}", def_id))
+    }
+}

compiler/rustc_passes/src/reachable.rs

@@ -307,6 +307,7 @@ impl<'tcx> ReachableContext<'tcx> {
             | Node::Ctor(..)
             | Node::Field(_)
             | Node::Ty(_)
+            | Node::Crate(_)
             | Node::MacroDef(_) => {}
             _ => {
                 bug!(

compiler/rustc_ty_utils/src/ty.rs

@@ -218,10 +218,6 @@ fn associated_items(tcx: TyCtxt<'_>, def_id: DefId) -> ty::AssociatedItems<'_> {
     ty::AssociatedItems::new(items)
 }
 
-fn def_span(tcx: TyCtxt<'_>, def_id: DefId) -> Span {
-    tcx.hir().span_if_local(def_id).unwrap()
-}
-
 fn def_ident_span(tcx: TyCtxt<'_>, def_id: DefId) -> Option<Span> {
     tcx.hir().get_if_local(def_id).and_then(|node| node.ident()).map(|ident| ident.span)
 }
@@ -495,7 +491,6 @@ pub fn provide(providers: &mut ty::query::Providers) {
         associated_item_def_ids,
         associated_items,
         adt_sized_constraint,
-        def_span,
         def_ident_span,
         param_env,
         param_env_reveal_all_normalized,

src/test/ui/lint/lint-const-item-mutation.stderr

@@ -109,14 +109,8 @@ LL |     VEC.push(0);
 note: mutable reference created due to call to this method
   --> $SRC_DIR/alloc/src/vec/mod.rs:LL:COL
    |
-LL | /     pub fn push(&mut self, value: T) {
-LL | |         // This will panic or abort if we would allocate > isize::MAX bytes
-LL | |         // or if the length increment would overflow for zero-sized types.
-LL | |         if self.len == self.buf.capacity() {
-...  |
-LL | |         }
-LL | |     }
-   | |_____^
+LL |     pub fn push(&mut self, value: T) {
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 note: `const` item defined here
   --> $DIR/lint-const-item-mutation.rs:31:1
    |