1 files changed, 344 insertions, 0 deletions
diff --git a/compiler/rustc_passes/src/hir_stats.rs b/compiler/rustc_passes/src/hir_stats.rs
new file mode 100644
index 000000000..a3be827a7
--- /dev/null
+++ b/compiler/rustc_passes/src/hir_stats.rs
@@ -0,0 +1,344 @@
+// The visitors in this module collect sizes and counts of the most important
+// pieces of AST and HIR. The resulting numbers are good approximations but not
+// completely accurate (some things might be counted twice, others missed).
+
+use rustc_ast::visit as ast_visit;
+use rustc_ast::visit::BoundKind;
+use rustc_ast::{self as ast, AttrId, NodeId};
+use rustc_data_structures::fx::{FxHashMap, FxHashSet};
+use rustc_hir as hir;
+use rustc_hir::intravisit as hir_visit;
+use rustc_hir::HirId;
+use rustc_middle::hir::map::Map;
+use rustc_middle::ty::TyCtxt;
+use rustc_middle::util::common::to_readable_str;
+use rustc_span::Span;
+
+#[derive(Copy, Clone, PartialEq, Eq, Hash)]
+enum Id {
+    Node(HirId),
+    Attr(AttrId),
+    None,
+}
+
+struct NodeData {
+    count: usize,
+    size: usize,
+}
+
+struct StatCollector<'k> {
+    krate: Option<Map<'k>>,
+    data: FxHashMap<&'static str, NodeData>,
+    seen: FxHashSet<Id>,
+}
+
+pub fn print_hir_stats(tcx: TyCtxt<'_>) {
+    let mut collector = StatCollector {
+        krate: Some(tcx.hir()),
+        data: FxHashMap::default(),
+        seen: FxHashSet::default(),
+    };
+    tcx.hir().walk_toplevel_module(&mut collector);
+    tcx.hir().walk_attributes(&mut collector);
+    collector.print("HIR STATS");
+}
+
+pub fn print_ast_stats(krate: &ast::Crate, title: &str) {
+    let mut collector =
+        StatCollector { krate: None, data: FxHashMap::default(), seen: FxHashSet::default() };
+    ast_visit::walk_crate(&mut collector, krate);
+    collector.print(title);
+}
+
+impl<'k> StatCollector<'k> {
+    fn record<T>(&mut self, label: &'static str, id: Id, node: &T) {
+        if id != Id::None && !self.seen.insert(id) {
+            return;
+        }
+
+        let entry = self.data.entry(label).or_insert(NodeData { count: 0, size: 0 });
+
+        entry.count += 1;
+        entry.size = std::mem::size_of_val(node);
+    }
+
+    fn print(&self, title: &str) {
+        let mut stats: Vec<_> = self.data.iter().collect();
+
+        stats.sort_by_key(|&(_, ref d)| d.count * d.size);
+
+        let mut total_size = 0;
+
+        eprintln!("\n{}\n", title);
+
+        eprintln!("{:<18}{:>18}{:>14}{:>14}", "Name", "Accumulated Size", "Count", "Item Size");
+        eprintln!("----------------------------------------------------------------");
+
+        for (label, data) in stats {
+            eprintln!(
+                "{:<18}{:>18}{:>14}{:>14}",
+                label,
+                to_readable_str(data.count * data.size),
+                to_readable_str(data.count),
+                to_readable_str(data.size)
+            );
+
+            total_size += data.count * data.size;
+        }
+        eprintln!("----------------------------------------------------------------");
+        eprintln!("{:<18}{:>18}\n", "Total", to_readable_str(total_size));
+    }
+}
+
+impl<'v> hir_visit::Visitor<'v> for StatCollector<'v> {
+    fn visit_param(&mut self, param: &'v hir::Param<'v>) {
+        self.record("Param", Id::Node(param.hir_id), param);
+        hir_visit::walk_param(self, param)
+    }
+
+    fn visit_nested_item(&mut self, id: hir::ItemId) {
+        let nested_item = self.krate.unwrap().item(id);
+        self.visit_item(nested_item)
+    }
+
+    fn visit_nested_trait_item(&mut self, trait_item_id: hir::TraitItemId) {
+        let nested_trait_item = self.krate.unwrap().trait_item(trait_item_id);
+        self.visit_trait_item(nested_trait_item)
+    }
+
+    fn visit_nested_impl_item(&mut self, impl_item_id: hir::ImplItemId) {
+        let nested_impl_item = self.krate.unwrap().impl_item(impl_item_id);
+        self.visit_impl_item(nested_impl_item)
+    }
+
+    fn visit_nested_foreign_item(&mut self, id: hir::ForeignItemId) {
+        let nested_foreign_item = self.krate.unwrap().foreign_item(id);
+        self.visit_foreign_item(nested_foreign_item);
+    }
+
+    fn visit_nested_body(&mut self, body_id: hir::BodyId) {
+        let nested_body = self.krate.unwrap().body(body_id);
+        self.visit_body(nested_body)
+    }
+
+    fn visit_item(&mut self, i: &'v hir::Item<'v>) {
+        self.record("Item", Id::Node(i.hir_id()), i);
+        hir_visit::walk_item(self, i)
+    }
+
+    fn visit_foreign_item(&mut self, i: &'v hir::ForeignItem<'v>) {
+        self.record("ForeignItem", Id::Node(i.hir_id()), i);
+        hir_visit::walk_foreign_item(self, i)
+    }
+
+    fn visit_local(&mut self, l: &'v hir::Local<'v>) {
+        self.record("Local", Id::Node(l.hir_id), l);
+        hir_visit::walk_local(self, l)
+    }
+
+    fn visit_block(&mut self, b: &'v hir::Block<'v>) {
+        self.record("Block", Id::Node(b.hir_id), b);
+        hir_visit::walk_block(self, b)
+    }
+
+    fn visit_stmt(&mut self, s: &'v hir::Stmt<'v>) {
+        self.record("Stmt", Id::Node(s.hir_id), s);
+        hir_visit::walk_stmt(self, s)
+    }
+
+    fn visit_arm(&mut self, a: &'v hir::Arm<'v>) {
+        self.record("Arm", Id::Node(a.hir_id), a);
+        hir_visit::walk_arm(self, a)
+    }
+
+    fn visit_pat(&mut self, p: &'v hir::Pat<'v>) {
+        self.record("Pat", Id::Node(p.hir_id), p);
+        hir_visit::walk_pat(self, p)
+    }
+
+    fn visit_expr(&mut self, ex: &'v hir::Expr<'v>) {
+        self.record("Expr", Id::Node(ex.hir_id), ex);
+        hir_visit::walk_expr(self, ex)
+    }
+
+    fn visit_ty(&mut self, t: &'v hir::Ty<'v>) {
+        self.record("Ty", Id::Node(t.hir_id), t);
+        hir_visit::walk_ty(self, t)
+    }
+
+    fn visit_fn(
+        &mut self,
+        fk: hir_visit::FnKind<'v>,
+        fd: &'v hir::FnDecl<'v>,
+        b: hir::BodyId,
+        s: Span,
+        id: hir::HirId,
+    ) {
+        self.record("FnDecl", Id::None, fd);
+        hir_visit::walk_fn(self, fk, fd, b, s, id)
+    }
+
+    fn visit_where_predicate(&mut self, predicate: &'v hir::WherePredicate<'v>) {
+        self.record("WherePredicate", Id::None, predicate);
+        hir_visit::walk_where_predicate(self, predicate)
+    }
+
+    fn visit_trait_item(&mut self, ti: &'v hir::TraitItem<'v>) {
+        self.record("TraitItem", Id::Node(ti.hir_id()), ti);
+        hir_visit::walk_trait_item(self, ti)
+    }
+
+    fn visit_impl_item(&mut self, ii: &'v hir::ImplItem<'v>) {
+        self.record("ImplItem", Id::Node(ii.hir_id()), ii);
+        hir_visit::walk_impl_item(self, ii)
+    }
+
+    fn visit_param_bound(&mut self, bounds: &'v hir::GenericBound<'v>) {
+        self.record("GenericBound", Id::None, bounds);
+        hir_visit::walk_param_bound(self, bounds)
+    }
+
+    fn visit_field_def(&mut self, s: &'v hir::FieldDef<'v>) {
+        self.record("FieldDef", Id::Node(s.hir_id), s);
+        hir_visit::walk_field_def(self, s)
+    }
+
+    fn visit_variant(
+        &mut self,
+        v: &'v hir::Variant<'v>,
+        g: &'v hir::Generics<'v>,
+        item_id: hir::HirId,
+    ) {
+        self.record("Variant", Id::None, v);
+        hir_visit::walk_variant(self, v, g, item_id)
+    }
+
+    fn visit_lifetime(&mut self, lifetime: &'v hir::Lifetime) {
+        self.record("Lifetime", Id::Node(lifetime.hir_id), lifetime);
+        hir_visit::walk_lifetime(self, lifetime)
+    }
+
+    fn visit_qpath(&mut self, qpath: &'v hir::QPath<'v>, id: hir::HirId, span: Span) {
+        self.record("QPath", Id::None, qpath);
+        hir_visit::walk_qpath(self, qpath, id, span)
+    }
+
+    fn visit_path(&mut self, path: &'v hir::Path<'v>, _id: hir::HirId) {
+        self.record("Path", Id::None, path);
+        hir_visit::walk_path(self, path)
+    }
+
+    fn visit_path_segment(&mut self, path_span: Span, path_segment: &'v hir::PathSegment<'v>) {
+        self.record("PathSegment", Id::None, path_segment);
+        hir_visit::walk_path_segment(self, path_span, path_segment)
+    }
+
+    fn visit_assoc_type_binding(&mut self, type_binding: &'v hir::TypeBinding<'v>) {
+        self.record("TypeBinding", Id::Node(type_binding.hir_id), type_binding);
+        hir_visit::walk_assoc_type_binding(self, type_binding)
+    }
+
+    fn visit_attribute(&mut self, attr: &'v ast::Attribute) {
+        self.record("Attribute", Id::Attr(attr.id), attr);
+    }
+}
+
+impl<'v> ast_visit::Visitor<'v> for StatCollector<'v> {
+    fn visit_foreign_item(&mut self, i: &'v ast::ForeignItem) {
+        self.record("ForeignItem", Id::None, i);
+        ast_visit::walk_foreign_item(self, i)
+    }
+
+    fn visit_item(&mut self, i: &'v ast::Item) {
+        self.record("Item", Id::None, i);
+        ast_visit::walk_item(self, i)
+    }
+
+    fn visit_local(&mut self, l: &'v ast::Local) {
+        self.record("Local", Id::None, l);
+        ast_visit::walk_local(self, l)
+    }
+
+    fn visit_block(&mut self, b: &'v ast::Block) {
+        self.record("Block", Id::None, b);
+        ast_visit::walk_block(self, b)
+    }
+
+    fn visit_stmt(&mut self, s: &'v ast::Stmt) {
+        self.record("Stmt", Id::None, s);
+        ast_visit::walk_stmt(self, s)
+    }
+
+    fn visit_arm(&mut self, a: &'v ast::Arm) {
+        self.record("Arm", Id::None, a);
+        ast_visit::walk_arm(self, a)
+    }
+
+    fn visit_pat(&mut self, p: &'v ast::Pat) {
+        self.record("Pat", Id::None, p);
+        ast_visit::walk_pat(self, p)
+    }
+
+    fn visit_expr(&mut self, ex: &'v ast::Expr) {
+        self.record("Expr", Id::None, ex);
+        ast_visit::walk_expr(self, ex)
+    }
+
+    fn visit_ty(&mut self, t: &'v ast::Ty) {
+        self.record("Ty", Id::None, t);
+        ast_visit::walk_ty(self, t)
+    }
+
+    fn visit_fn(&mut self, fk: ast_visit::FnKind<'v>, s: Span, _: NodeId) {
+        self.record("FnDecl", Id::None, fk.decl());
+        ast_visit::walk_fn(self, fk, s)
+    }
+
+    fn visit_assoc_item(&mut self, item: &'v ast::AssocItem, ctxt: ast_visit::AssocCtxt) {
+        let label = match ctxt {
+            ast_visit::AssocCtxt::Trait => "TraitItem",
+            ast_visit::AssocCtxt::Impl => "ImplItem",
+        };
+        self.record(label, Id::None, item);
+        ast_visit::walk_assoc_item(self, item, ctxt);
+    }
+
+    fn visit_param_bound(&mut self, bounds: &'v ast::GenericBound, _ctxt: BoundKind) {
+        self.record("GenericBound", Id::None, bounds);
+        ast_visit::walk_param_bound(self, bounds)
+    }
+
+    fn visit_field_def(&mut self, s: &'v ast::FieldDef) {
+        self.record("FieldDef", Id::None, s);
+        ast_visit::walk_field_def(self, s)
+    }
+
+    fn visit_variant(&mut self, v: &'v ast::Variant) {
+        self.record("Variant", Id::None, v);
+        ast_visit::walk_variant(self, v)
+    }
+
+    fn visit_lifetime(&mut self, lifetime: &'v ast::Lifetime, _: ast_visit::LifetimeCtxt) {
+        self.record("Lifetime", Id::None, lifetime);
+        ast_visit::walk_lifetime(self, lifetime)
+    }
+
+    fn visit_mac_call(&mut self, mac: &'v ast::MacCall) {
+        self.record("MacCall", Id::None, mac);
+        ast_visit::walk_mac(self, mac)
+    }
+
+    fn visit_path_segment(&mut self, path_span: Span, path_segment: &'v ast::PathSegment) {
+        self.record("PathSegment", Id::None, path_segment);
+        ast_visit::walk_path_segment(self, path_span, path_segment)
+    }
+
+    fn visit_assoc_constraint(&mut self, constraint: &'v ast::AssocConstraint) {
+        self.record("AssocConstraint", Id::None, constraint);
+        ast_visit::walk_assoc_constraint(self, constraint)
+    }
+
+    fn visit_attribute(&mut self, attr: &'v ast::Attribute) {
+        self.record("Attribute", Id::None, attr);
+    }
+}