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-rw-r--r--compiler/rustc_expand/messages.ftl3
-rw-r--r--compiler/rustc_expand/src/base.rs6
-rw-r--r--compiler/rustc_expand/src/config.rs11
-rw-r--r--compiler/rustc_expand/src/errors.rs4
-rw-r--r--compiler/rustc_expand/src/expand.rs190
-rw-r--r--compiler/rustc_expand/src/lib.rs1
-rw-r--r--compiler/rustc_expand/src/mbe/macro_check.rs25
-rw-r--r--compiler/rustc_expand/src/stats.rs171
8 files changed, 345 insertions, 66 deletions
diff --git a/compiler/rustc_expand/messages.ftl b/compiler/rustc_expand/messages.ftl
index f26c7c1ba0b..8b7c47dad99 100644
--- a/compiler/rustc_expand/messages.ftl
+++ b/compiler/rustc_expand/messages.ftl
@@ -62,6 +62,7 @@ expand_feature_not_allowed =
 expand_feature_removed =
     feature has been removed
     .label = feature has been removed
+    .note = removed in {$removed_rustc_version} (you are using {$current_rustc_version}){$pull_note}
     .reason = {$reason}
 
 expand_glob_delegation_outside_impls =
@@ -112,7 +113,7 @@ expand_meta_var_expr_unrecognized_var =
     variable `{$key}` is not recognized in meta-variable expression
 
 expand_missing_fragment_specifier = missing fragment specifier
-    .note = fragment specifiers must be specified in the 2024 edition
+    .note = fragment specifiers must be provided
     .suggestion_add_fragspec = try adding a specifier here
     .valid = {$valid}
 
diff --git a/compiler/rustc_expand/src/base.rs b/compiler/rustc_expand/src/base.rs
index c7b975d8f3e..311dadb53c4 100644
--- a/compiler/rustc_expand/src/base.rs
+++ b/compiler/rustc_expand/src/base.rs
@@ -12,7 +12,7 @@ use rustc_ast::tokenstream::TokenStream;
 use rustc_ast::visit::{AssocCtxt, Visitor};
 use rustc_ast::{self as ast, AttrVec, Attribute, HasAttrs, Item, NodeId, PatKind};
 use rustc_attr_data_structures::{AttributeKind, Deprecation, Stability, find_attr};
-use rustc_data_structures::fx::FxIndexMap;
+use rustc_data_structures::fx::{FxHashMap, FxIndexMap};
 use rustc_data_structures::sync;
 use rustc_errors::{DiagCtxtHandle, ErrorGuaranteed, PResult};
 use rustc_feature::Features;
@@ -727,6 +727,7 @@ pub enum SyntaxExtensionKind {
     /// A trivial attribute "macro" that does nothing,
     /// only keeps the attribute and marks it as inert,
     /// thus making it ineligible for further expansion.
+    /// E.g. `#[default]`, `#[rustfmt::skip]`.
     NonMacroAttr,
 
     /// A token-based derive macro.
@@ -1189,6 +1190,8 @@ pub struct ExtCtxt<'a> {
     /// in the AST, but insert it here so that we know
     /// not to expand it again.
     pub(super) expanded_inert_attrs: MarkedAttrs,
+    /// `-Zmacro-stats` data.
+    pub macro_stats: FxHashMap<(Symbol, MacroKind), crate::stats::MacroStat>, // njn: quals
 }
 
 impl<'a> ExtCtxt<'a> {
@@ -1218,6 +1221,7 @@ impl<'a> ExtCtxt<'a> {
             expansions: FxIndexMap::default(),
             expanded_inert_attrs: MarkedAttrs::new(),
             buffered_early_lint: vec![],
+            macro_stats: Default::default(),
         }
     }
 
diff --git a/compiler/rustc_expand/src/config.rs b/compiler/rustc_expand/src/config.rs
index c50ab5959e2..9a359e9b031 100644
--- a/compiler/rustc_expand/src/config.rs
+++ b/compiler/rustc_expand/src/config.rs
@@ -80,9 +80,20 @@ pub fn features(sess: &Session, krate_attrs: &[Attribute], crate_name: Symbol) -
 
             // If the enabled feature has been removed, issue an error.
             if let Some(f) = REMOVED_LANG_FEATURES.iter().find(|f| name == f.feature.name) {
+                let pull_note = if let Some(pull) = f.pull {
+                    format!(
+                        "; see <https://github.com/rust-lang/rust/pull/{}> for more information",
+                        pull
+                    )
+                } else {
+                    "".to_owned()
+                };
                 sess.dcx().emit_err(FeatureRemoved {
                     span: mi.span(),
                     reason: f.reason.map(|reason| FeatureRemovedReason { reason }),
+                    removed_rustc_version: f.feature.since,
+                    current_rustc_version: sess.cfg_version,
+                    pull_note,
                 });
                 continue;
             }
diff --git a/compiler/rustc_expand/src/errors.rs b/compiler/rustc_expand/src/errors.rs
index 89bdc7b6dfa..ec0af67c046 100644
--- a/compiler/rustc_expand/src/errors.rs
+++ b/compiler/rustc_expand/src/errors.rs
@@ -154,12 +154,16 @@ pub(crate) struct HelperAttributeNameInvalid {
 
 #[derive(Diagnostic)]
 #[diag(expand_feature_removed, code = E0557)]
+#[note]
 pub(crate) struct FeatureRemoved<'a> {
     #[primary_span]
     #[label]
     pub span: Span,
     #[subdiagnostic]
     pub reason: Option<FeatureRemovedReason<'a>>,
+    pub removed_rustc_version: &'a str,
+    pub current_rustc_version: &'a str,
+    pub pull_note: String,
 }
 
 #[derive(Subdiagnostic)]
diff --git a/compiler/rustc_expand/src/expand.rs b/compiler/rustc_expand/src/expand.rs
index 569165a64e5..3cfeb01ea47 100644
--- a/compiler/rustc_expand/src/expand.rs
+++ b/compiler/rustc_expand/src/expand.rs
@@ -42,13 +42,22 @@ use crate::module::{
     DirOwnership, ParsedExternalMod, mod_dir_path, mod_file_path_from_attr, parse_external_mod,
 };
 use crate::placeholders::{PlaceholderExpander, placeholder};
+use crate::stats::*;
 
 macro_rules! ast_fragments {
     (
         $($Kind:ident($AstTy:ty) {
             $kind_name:expr;
-            $(one fn $mut_visit_ast:ident; fn $visit_ast:ident;)?
-            $(many fn $flat_map_ast_elt:ident; fn $visit_ast_elt:ident($($args:tt)*);)?
+            $(one
+                fn $mut_visit_ast:ident;
+                fn $visit_ast:ident;
+                fn $ast_to_string:path;
+            )?
+            $(many
+                fn $flat_map_ast_elt:ident;
+                fn $visit_ast_elt:ident($($args:tt)*);
+                fn $ast_to_string_elt:path;
+            )?
             fn $make_ast:ident;
         })*
     ) => {
@@ -61,7 +70,7 @@ macro_rules! ast_fragments {
         }
 
         /// "Discriminant" of an AST fragment.
-        #[derive(Copy, Clone, PartialEq, Eq)]
+        #[derive(Copy, Clone, Debug, PartialEq, Eq)]
         pub enum AstFragmentKind {
             OptExpr,
             MethodReceiverExpr,
@@ -151,6 +160,21 @@ macro_rules! ast_fragments {
                 }
                 V::Result::output()
             }
+
+            pub(crate) fn to_string(&self) -> String {
+                match self {
+                    AstFragment::OptExpr(Some(expr)) => pprust::expr_to_string(expr),
+                    AstFragment::OptExpr(None) => unreachable!(),
+                    AstFragment::MethodReceiverExpr(expr) => pprust::expr_to_string(expr),
+                    $($(AstFragment::$Kind(ast) => $ast_to_string(ast),)?)*
+                    $($(
+                        AstFragment::$Kind(ast) => {
+                            // The closure unwraps a `P` if present, or does nothing otherwise.
+                            elems_to_string(&*ast, |ast| $ast_to_string_elt(&*ast))
+                        }
+                    )?)*
+                }
+            }
         }
 
         impl<'a> MacResult for crate::mbe::macro_rules::ParserAnyMacro<'a> {
@@ -163,76 +187,98 @@ macro_rules! ast_fragments {
 }
 
 ast_fragments! {
-    Expr(P<ast::Expr>) { "expression"; one fn visit_expr; fn visit_expr; fn make_expr; }
-    Pat(P<ast::Pat>) { "pattern"; one fn visit_pat; fn visit_pat; fn make_pat; }
-    Ty(P<ast::Ty>) { "type"; one fn visit_ty; fn visit_ty; fn make_ty; }
+    Expr(P<ast::Expr>) {
+        "expression";
+        one fn visit_expr; fn visit_expr; fn pprust::expr_to_string;
+        fn make_expr;
+    }
+    Pat(P<ast::Pat>) {
+        "pattern";
+        one fn visit_pat; fn visit_pat; fn pprust::pat_to_string;
+        fn make_pat;
+    }
+    Ty(P<ast::Ty>) {
+        "type";
+        one fn visit_ty; fn visit_ty; fn pprust::ty_to_string;
+        fn make_ty;
+    }
     Stmts(SmallVec<[ast::Stmt; 1]>) {
-        "statement"; many fn flat_map_stmt; fn visit_stmt(); fn make_stmts;
+        "statement";
+        many fn flat_map_stmt; fn visit_stmt(); fn pprust::stmt_to_string;
+        fn make_stmts;
     }
     Items(SmallVec<[P<ast::Item>; 1]>) {
-        "item"; many fn flat_map_item; fn visit_item(); fn make_items;
+        "item";
+        many fn flat_map_item; fn visit_item(); fn pprust::item_to_string;
+        fn make_items;
     }
     TraitItems(SmallVec<[P<ast::AssocItem>; 1]>) {
         "trait item";
-        many fn flat_map_assoc_item;
-        fn visit_assoc_item(AssocCtxt::Trait);
+        many fn flat_map_assoc_item; fn visit_assoc_item(AssocCtxt::Trait);
+            fn pprust::assoc_item_to_string;
         fn make_trait_items;
     }
     ImplItems(SmallVec<[P<ast::AssocItem>; 1]>) {
         "impl item";
-        many fn flat_map_assoc_item;
-        fn visit_assoc_item(AssocCtxt::Impl { of_trait: false });
+        many fn flat_map_assoc_item; fn visit_assoc_item(AssocCtxt::Impl { of_trait: false });
+            fn pprust::assoc_item_to_string;
         fn make_impl_items;
     }
     TraitImplItems(SmallVec<[P<ast::AssocItem>; 1]>) {
         "impl item";
-        many fn flat_map_assoc_item;
-        fn visit_assoc_item(AssocCtxt::Impl { of_trait: true });
+        many fn flat_map_assoc_item; fn visit_assoc_item(AssocCtxt::Impl { of_trait: true });
+            fn pprust::assoc_item_to_string;
         fn make_trait_impl_items;
     }
     ForeignItems(SmallVec<[P<ast::ForeignItem>; 1]>) {
         "foreign item";
-        many fn flat_map_foreign_item;
-        fn visit_foreign_item();
+        many fn flat_map_foreign_item; fn visit_foreign_item(); fn pprust::foreign_item_to_string;
         fn make_foreign_items;
     }
     Arms(SmallVec<[ast::Arm; 1]>) {
-        "match arm"; many fn flat_map_arm; fn visit_arm(); fn make_arms;
+        "match arm";
+        many fn flat_map_arm; fn visit_arm(); fn unreachable_to_string;
+        fn make_arms;
     }
     ExprFields(SmallVec<[ast::ExprField; 1]>) {
-        "field expression"; many fn flat_map_expr_field; fn visit_expr_field(); fn make_expr_fields;
+        "field expression";
+        many fn flat_map_expr_field; fn visit_expr_field(); fn unreachable_to_string;
+        fn make_expr_fields;
     }
     PatFields(SmallVec<[ast::PatField; 1]>) {
         "field pattern";
-        many fn flat_map_pat_field;
-        fn visit_pat_field();
+        many fn flat_map_pat_field; fn visit_pat_field(); fn unreachable_to_string;
         fn make_pat_fields;
     }
     GenericParams(SmallVec<[ast::GenericParam; 1]>) {
         "generic parameter";
-        many fn flat_map_generic_param;
-        fn visit_generic_param();
+        many fn flat_map_generic_param; fn visit_generic_param(); fn unreachable_to_string;
         fn make_generic_params;
     }
     Params(SmallVec<[ast::Param; 1]>) {
-        "function parameter"; many fn flat_map_param; fn visit_param(); fn make_params;
+        "function parameter";
+        many fn flat_map_param; fn visit_param(); fn unreachable_to_string;
+        fn make_params;
     }
     FieldDefs(SmallVec<[ast::FieldDef; 1]>) {
         "field";
-        many fn flat_map_field_def;
-        fn visit_field_def();
+        many fn flat_map_field_def; fn visit_field_def(); fn unreachable_to_string;
         fn make_field_defs;
     }
     Variants(SmallVec<[ast::Variant; 1]>) {
-        "variant"; many fn flat_map_variant; fn visit_variant(); fn make_variants;
+        "variant"; many fn flat_map_variant; fn visit_variant(); fn unreachable_to_string;
+        fn make_variants;
     }
     WherePredicates(SmallVec<[ast::WherePredicate; 1]>) {
         "where predicate";
-        many fn flat_map_where_predicate;
-        fn visit_where_predicate();
+        many fn flat_map_where_predicate; fn visit_where_predicate(); fn unreachable_to_string;
         fn make_where_predicates;
-     }
-    Crate(ast::Crate) { "crate"; one fn visit_crate; fn visit_crate; fn make_crate; }
+    }
+    Crate(ast::Crate) {
+        "crate";
+        one fn visit_crate; fn visit_crate; fn unreachable_to_string;
+        fn make_crate;
+    }
 }
 
 pub enum SupportsMacroExpansion {
@@ -270,7 +316,7 @@ impl AstFragmentKind {
         }
     }
 
-    fn expect_from_annotatables<I: IntoIterator<Item = Annotatable>>(
+    pub(crate) fn expect_from_annotatables<I: IntoIterator<Item = Annotatable>>(
         self,
         items: I,
     ) -> AstFragment {
@@ -686,13 +732,26 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
             return ExpandResult::Ready(invoc.fragment_kind.dummy(invoc.span(), guar));
         }
 
+        let macro_stats = self.cx.sess.opts.unstable_opts.macro_stats;
+
         let (fragment_kind, span) = (invoc.fragment_kind, invoc.span());
         ExpandResult::Ready(match invoc.kind {
             InvocationKind::Bang { mac, span } => match ext {
                 SyntaxExtensionKind::Bang(expander) => {
                     match expander.expand(self.cx, span, mac.args.tokens.clone()) {
                         Ok(tok_result) => {
-                            self.parse_ast_fragment(tok_result, fragment_kind, &mac.path, span)
+                            let fragment =
+                                self.parse_ast_fragment(tok_result, fragment_kind, &mac.path, span);
+                            if macro_stats {
+                                update_bang_macro_stats(
+                                    self.cx,
+                                    fragment_kind,
+                                    span,
+                                    mac,
+                                    &fragment,
+                                );
+                            }
+                            fragment
                         }
                         Err(guar) => return ExpandResult::Ready(fragment_kind.dummy(span, guar)),
                     }
@@ -708,13 +767,15 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
                             });
                         }
                     };
-                    let result = if let Some(result) = fragment_kind.make_from(tok_result) {
-                        result
+                    if let Some(fragment) = fragment_kind.make_from(tok_result) {
+                        if macro_stats {
+                            update_bang_macro_stats(self.cx, fragment_kind, span, mac, &fragment);
+                        }
+                        fragment
                     } else {
                         let guar = self.error_wrong_fragment_kind(fragment_kind, &mac, span);
                         fragment_kind.dummy(span, guar)
-                    };
-                    result
+                    }
                 }
                 _ => unreachable!(),
             },
@@ -746,24 +807,39 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
                         }
                         _ => item.to_tokens(),
                     };
-                    let attr_item = attr.unwrap_normal_item();
+                    let attr_item = attr.get_normal_item();
                     if let AttrArgs::Eq { .. } = attr_item.args {
                         self.cx.dcx().emit_err(UnsupportedKeyValue { span });
                     }
                     let inner_tokens = attr_item.args.inner_tokens();
                     match expander.expand(self.cx, span, inner_tokens, tokens) {
-                        Ok(tok_result) => self.parse_ast_fragment(
-                            tok_result,
-                            fragment_kind,
-                            &attr_item.path,
-                            span,
-                        ),
+                        Ok(tok_result) => {
+                            let fragment = self.parse_ast_fragment(
+                                tok_result,
+                                fragment_kind,
+                                &attr_item.path,
+                                span,
+                            );
+                            if macro_stats {
+                                update_attr_macro_stats(
+                                    self.cx,
+                                    fragment_kind,
+                                    span,
+                                    &attr_item.path,
+                                    &attr,
+                                    item,
+                                    &fragment,
+                                );
+                            }
+                            fragment
+                        }
                         Err(guar) => return ExpandResult::Ready(fragment_kind.dummy(span, guar)),
                     }
                 }
                 SyntaxExtensionKind::LegacyAttr(expander) => {
                     match validate_attr::parse_meta(&self.cx.sess.psess, &attr) {
                         Ok(meta) => {
+                            let item_clone = macro_stats.then(|| item.clone());
                             let items = match expander.expand(self.cx, span, &meta, item, false) {
                                 ExpandResult::Ready(items) => items,
                                 ExpandResult::Retry(item) => {
@@ -782,7 +858,19 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
                                 let guar = self.cx.dcx().emit_err(RemoveExprNotSupported { span });
                                 fragment_kind.dummy(span, guar)
                             } else {
-                                fragment_kind.expect_from_annotatables(items)
+                                let fragment = fragment_kind.expect_from_annotatables(items);
+                                if macro_stats {
+                                    update_attr_macro_stats(
+                                        self.cx,
+                                        fragment_kind,
+                                        span,
+                                        &meta.path,
+                                        &attr,
+                                        item_clone.unwrap(),
+                                        &fragment,
+                                    );
+                                }
+                                fragment
                             }
                         }
                         Err(err) => {
@@ -792,6 +880,7 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
                     }
                 }
                 SyntaxExtensionKind::NonMacroAttr => {
+                    // `-Zmacro-stats` ignores these because they don't do any real expansion.
                     self.cx.expanded_inert_attrs.mark(&attr);
                     item.visit_attrs(|attrs| attrs.insert(pos, attr));
                     fragment_kind.expect_from_annotatables(iter::once(item))
@@ -822,7 +911,17 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
                             });
                         }
                     };
-                    fragment_kind.expect_from_annotatables(items)
+                    let fragment = fragment_kind.expect_from_annotatables(items);
+                    if macro_stats {
+                        update_derive_macro_stats(
+                            self.cx,
+                            fragment_kind,
+                            span,
+                            &meta.path,
+                            &fragment,
+                        );
+                    }
+                    fragment
                 }
                 _ => unreachable!(),
             },
@@ -852,6 +951,7 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
                 let single_delegations = build_single_delegations::<Node>(
                     self.cx, deleg, &item, &suffixes, item.span, true,
                 );
+                // `-Zmacro-stats` ignores these because they don't seem important.
                 fragment_kind.expect_from_annotatables(
                     single_delegations
                         .map(|item| Annotatable::AssocItem(P(item), AssocCtxt::Impl { of_trait })),
diff --git a/compiler/rustc_expand/src/lib.rs b/compiler/rustc_expand/src/lib.rs
index 515d82296ca..64be7649775 100644
--- a/compiler/rustc_expand/src/lib.rs
+++ b/compiler/rustc_expand/src/lib.rs
@@ -20,6 +20,7 @@ mod errors;
 mod mbe;
 mod placeholders;
 mod proc_macro_server;
+mod stats;
 
 pub use mbe::macro_rules::compile_declarative_macro;
 pub mod base;
diff --git a/compiler/rustc_expand/src/mbe/macro_check.rs b/compiler/rustc_expand/src/mbe/macro_check.rs
index 1a2db233b7a..3cd803c3e84 100644
--- a/compiler/rustc_expand/src/mbe/macro_check.rs
+++ b/compiler/rustc_expand/src/mbe/macro_check.rs
@@ -112,9 +112,8 @@ use rustc_ast::{DUMMY_NODE_ID, NodeId};
 use rustc_data_structures::fx::FxHashMap;
 use rustc_errors::MultiSpan;
 use rustc_lint_defs::BuiltinLintDiag;
-use rustc_session::lint::builtin::{META_VARIABLE_MISUSE, MISSING_FRAGMENT_SPECIFIER};
+use rustc_session::lint::builtin::META_VARIABLE_MISUSE;
 use rustc_session::parse::ParseSess;
-use rustc_span::edition::Edition;
 use rustc_span::{ErrorGuaranteed, MacroRulesNormalizedIdent, Span, kw};
 use smallvec::SmallVec;
 
@@ -266,23 +265,11 @@ fn check_binders(
         // Similarly, this can only happen when checking a toplevel macro.
         TokenTree::MetaVarDecl(span, name, kind) => {
             if kind.is_none() && node_id != DUMMY_NODE_ID {
-                // FIXME: Report this as a hard error eventually and remove equivalent errors from
-                // `parse_tt_inner` and `nameize`. Until then the error may be reported twice, once
-                // as a hard error and then once as a buffered lint.
-                if span.edition() >= Edition::Edition2024 {
-                    psess.dcx().emit_err(errors::MissingFragmentSpecifier {
-                        span,
-                        add_span: span.shrink_to_hi(),
-                        valid: VALID_FRAGMENT_NAMES_MSG,
-                    });
-                } else {
-                    psess.buffer_lint(
-                        MISSING_FRAGMENT_SPECIFIER,
-                        span,
-                        node_id,
-                        BuiltinLintDiag::MissingFragmentSpecifier,
-                    );
-                }
+                psess.dcx().emit_err(errors::MissingFragmentSpecifier {
+                    span,
+                    add_span: span.shrink_to_hi(),
+                    valid: VALID_FRAGMENT_NAMES_MSG,
+                });
             }
             if !macros.is_empty() {
                 psess.dcx().span_bug(span, "unexpected MetaVarDecl in nested lhs");
diff --git a/compiler/rustc_expand/src/stats.rs b/compiler/rustc_expand/src/stats.rs
new file mode 100644
index 00000000000..6b2ad30dffd
--- /dev/null
+++ b/compiler/rustc_expand/src/stats.rs
@@ -0,0 +1,171 @@
+use std::iter;
+
+use rustc_ast::ptr::P;
+use rustc_ast::{self as ast, DUMMY_NODE_ID, Expr, ExprKind};
+use rustc_ast_pretty::pprust;
+use rustc_span::hygiene::{ExpnKind, MacroKind};
+use rustc_span::{Span, Symbol, kw, sym};
+use smallvec::SmallVec;
+
+use crate::base::{Annotatable, ExtCtxt};
+use crate::expand::{AstFragment, AstFragmentKind};
+
+#[derive(Default)]
+pub struct MacroStat {
+    /// Number of uses of the macro.
+    pub uses: usize,
+
+    /// Net increase in number of lines of code (when pretty-printed), i.e.
+    /// `lines(output) - lines(invocation)`. Can be negative because a macro
+    /// output may be smaller than the invocation.
+    pub lines: isize,
+
+    /// Net increase in number of lines of code (when pretty-printed), i.e.
+    /// `bytes(output) - bytes(invocation)`. Can be negative because a macro
+    /// output may be smaller than the invocation.
+    pub bytes: isize,
+}
+
+pub(crate) fn elems_to_string<T>(elems: &SmallVec<[T; 1]>, f: impl Fn(&T) -> String) -> String {
+    let mut s = String::new();
+    for (i, elem) in elems.iter().enumerate() {
+        if i > 0 {
+            s.push('\n');
+        }
+        s.push_str(&f(elem));
+    }
+    s
+}
+
+pub(crate) fn unreachable_to_string<T>(_: &T) -> String {
+    unreachable!()
+}
+
+pub(crate) fn update_bang_macro_stats(
+    ecx: &mut ExtCtxt<'_>,
+    fragment_kind: AstFragmentKind,
+    span: Span,
+    mac: P<ast::MacCall>,
+    fragment: &AstFragment,
+) {
+    // Does this path match any of the include macros, e.g. `include!`?
+    // Ignore them. They would have large numbers but are entirely
+    // unsurprising and uninteresting.
+    let is_include_path = mac.path == sym::include
+        || mac.path == sym::include_bytes
+        || mac.path == sym::include_str
+        || mac.path == [sym::std, sym::include].as_slice() // std::include
+        || mac.path == [sym::std, sym::include_bytes].as_slice() // std::include_bytes
+        || mac.path == [sym::std, sym::include_str].as_slice(); // std::include_str
+    if is_include_path {
+        return;
+    }
+
+    // The call itself (e.g. `println!("hi")`) is the input. Need to wrap
+    // `mac` in something printable; `ast::Expr` is as good as anything
+    // else.
+    let expr = Expr {
+        id: DUMMY_NODE_ID,
+        kind: ExprKind::MacCall(mac),
+        span: Default::default(),
+        attrs: Default::default(),
+        tokens: None,
+    };
+    let input = pprust::expr_to_string(&expr);
+
+    // Get `mac` back out of `expr`.
+    let ast::Expr { kind: ExprKind::MacCall(mac), .. } = expr else { unreachable!() };
+
+    update_macro_stats(ecx, MacroKind::Bang, fragment_kind, span, &mac.path, &input, fragment);
+}
+
+pub(crate) fn update_attr_macro_stats(
+    ecx: &mut ExtCtxt<'_>,
+    fragment_kind: AstFragmentKind,
+    span: Span,
+    path: &ast::Path,
+    attr: &ast::Attribute,
+    item: Annotatable,
+    fragment: &AstFragment,
+) {
+    // Does this path match `#[derive(...)]` in any of its forms? If so,
+    // ignore it because the individual derives will go through the
+    // `Invocation::Derive` handling separately.
+    let is_derive_path = *path == sym::derive
+        // ::core::prelude::v1::derive
+        || *path == [kw::PathRoot, sym::core, sym::prelude, sym::v1, sym::derive].as_slice();
+    if is_derive_path {
+        return;
+    }
+
+    // The attribute plus the item itself constitute the input, which we
+    // measure.
+    let input = format!(
+        "{}\n{}",
+        pprust::attribute_to_string(attr),
+        fragment_kind.expect_from_annotatables(iter::once(item)).to_string(),
+    );
+    update_macro_stats(ecx, MacroKind::Attr, fragment_kind, span, path, &input, fragment);
+}
+
+pub(crate) fn update_derive_macro_stats(
+    ecx: &mut ExtCtxt<'_>,
+    fragment_kind: AstFragmentKind,
+    span: Span,
+    path: &ast::Path,
+    fragment: &AstFragment,
+) {
+    // Use something like `#[derive(Clone)]` for the measured input, even
+    // though it may have actually appeared in a multi-derive attribute
+    // like `#[derive(Clone, Copy, Debug)]`.
+    let input = format!("#[derive({})]", pprust::path_to_string(path));
+    update_macro_stats(ecx, MacroKind::Derive, fragment_kind, span, path, &input, fragment);
+}
+
+pub(crate) fn update_macro_stats(
+    ecx: &mut ExtCtxt<'_>,
+    macro_kind: MacroKind,
+    fragment_kind: AstFragmentKind,
+    span: Span,
+    path: &ast::Path,
+    input: &str,
+    fragment: &AstFragment,
+) {
+    fn lines_and_bytes(s: &str) -> (usize, usize) {
+        (s.trim_end().split('\n').count(), s.len())
+    }
+
+    // Measure the size of the output by pretty-printing it and counting
+    // the lines and bytes.
+    let name = Symbol::intern(&pprust::path_to_string(path));
+    let output = fragment.to_string();
+    let (in_l, in_b) = lines_and_bytes(input);
+    let (out_l, out_b) = lines_and_bytes(&output);
+
+    // This code is useful for debugging `-Zmacro-stats`. For every
+    // invocation it prints the full input and output.
+    if false {
+        let name = ExpnKind::Macro(macro_kind, name).descr();
+        let crate_name = &ecx.ecfg.crate_name;
+        let span = ecx
+            .sess
+            .source_map()
+            .span_to_string(span, rustc_span::FileNameDisplayPreference::Local);
+        eprint!(
+            "\
+            -------------------------------\n\
+            {name}: [{crate_name}] ({fragment_kind:?}) {span}\n\
+            -------------------------------\n\
+            {input}\n\
+            -- ({in_l} lines, {in_b} bytes) --> ({out_l} lines, {out_b} bytes) --\n\
+            {output}\n\
+        "
+        );
+    }
+
+    // The recorded size is the difference between the input and the output.
+    let entry = ecx.macro_stats.entry((name, macro_kind)).or_insert(MacroStat::default());
+    entry.uses += 1;
+    entry.lines += out_l as isize - in_l as isize;
+    entry.bytes += out_b as isize - in_b as isize;
+}