2 files changed, 214 insertions, 0 deletions

diff --git a/crates/mbe/src/benchmark.rs b/crates/mbe/src/benchmark.rs
new file mode 100644
index 000000000..0d0acd589
--- /dev/null
+++ b/crates/mbe/src/benchmark.rs
@@ -0,0 +1,211 @@
+//! This module add real world mbe example for benchmark tests
+
+use rustc_hash::FxHashMap;
+use syntax::{
+    ast::{self, NameOwner},
+    AstNode, SmolStr,
+};
+use test_utils::{bench, bench_fixture, skip_slow_tests};
+
+use crate::{
+    ast_to_token_tree,
+    parser::{Op, RepeatKind, Separator},
+    MacroRules,
+};
+
+#[test]
+fn benchmark_parse_macro_rules() {
+    if skip_slow_tests() {
+        return;
+    }
+    let rules = macro_rules_fixtures_tt();
+    let hash: usize = {
+        let _pt = bench("mbe parse macro rules");
+        rules.values().map(|it| MacroRules::parse(it).unwrap().rules.len()).sum()
+    };
+    assert_eq!(hash, 1144);
+}
+
+#[test]
+fn benchmark_expand_macro_rules() {
+    if skip_slow_tests() {
+        return;
+    }
+    let rules = macro_rules_fixtures();
+    let invocations = invocation_fixtures(&rules);
+
+    let hash: usize = {
+        let _pt = bench("mbe expand macro rules");
+        invocations
+            .into_iter()
+            .map(|(id, tt)| {
+                let res = rules[&id].expand(&tt);
+                if res.err.is_some() {
+                    // FIXME:
+                    // Currently `invocation_fixtures` will generate some correct invocations but
+                    // cannot be expanded by mbe. We ignore errors here.
+                    // See: https://github.com/rust-analyzer/rust-analyzer/issues/4777
+                    eprintln!("err from {} {:?}", id, res.err);
+                }
+                res.value.token_trees.len()
+            })
+            .sum()
+    };
+    assert_eq!(hash, 66995);
+}
+
+fn macro_rules_fixtures() -> FxHashMap<String, MacroRules> {
+    macro_rules_fixtures_tt()
+        .into_iter()
+        .map(|(id, tt)| (id, MacroRules::parse(&tt).unwrap()))
+        .collect()
+}
+
+fn macro_rules_fixtures_tt() -> FxHashMap<String, tt::Subtree> {
+    let fixture = bench_fixture::numerous_macro_rules();
+    let source_file = ast::SourceFile::parse(&fixture).ok().unwrap();
+
+    source_file
+        .syntax()
+        .descendants()
+        .filter_map(ast::MacroRules::cast)
+        .map(|rule| {
+            let id = rule.name().unwrap().to_string();
+            let (def_tt, _) = ast_to_token_tree(&rule.token_tree().unwrap()).unwrap();
+            (id, def_tt)
+        })
+        .collect()
+}
+
+// Generate random invocation fixtures from rules
+fn invocation_fixtures(rules: &FxHashMap<String, MacroRules>) -> Vec<(String, tt::Subtree)> {
+    let mut seed = 123456789;
+    let mut res = Vec::new();
+
+    for (name, it) in rules {
+        for rule in &it.rules {
+            // Generate twice
+            for _ in 0..2 {
+                let mut subtree = tt::Subtree::default();
+                for op in rule.lhs.iter() {
+                    collect_from_op(op, &mut subtree, &mut seed);
+                }
+                res.push((name.clone(), subtree));
+            }
+        }
+    }
+    return res;
+
+    fn collect_from_op(op: &Op, parent: &mut tt::Subtree, seed: &mut usize) {
+        return match op {
+            Op::Var { kind, .. } => match kind.as_ref().map(|it| it.as_str()) {
+                Some("ident") => parent.token_trees.push(make_ident("foo")),
+                Some("ty") => parent.token_trees.push(make_ident("Foo")),
+                Some("tt") => parent.token_trees.push(make_ident("foo")),
+                Some("vis") => parent.token_trees.push(make_ident("pub")),
+                Some("pat") => parent.token_trees.push(make_ident("foo")),
+                Some("path") => parent.token_trees.push(make_ident("foo")),
+                Some("literal") => parent.token_trees.push(make_literal("1")),
+                Some("expr") => parent.token_trees.push(make_ident("foo").into()),
+                Some("lifetime") => {
+                    parent.token_trees.push(make_punct('\''));
+                    parent.token_trees.push(make_ident("a"));
+                }
+                Some("block") => {
+                    parent.token_trees.push(make_subtree(tt::DelimiterKind::Brace, None))
+                }
+                Some("item") => {
+                    parent.token_trees.push(make_ident("fn"));
+                    parent.token_trees.push(make_ident("foo"));
+                    parent.token_trees.push(make_subtree(tt::DelimiterKind::Parenthesis, None));
+                    parent.token_trees.push(make_subtree(tt::DelimiterKind::Brace, None));
+                }
+                Some("meta") => {
+                    parent.token_trees.push(make_ident("foo"));
+                    parent.token_trees.push(make_subtree(tt::DelimiterKind::Parenthesis, None));
+                }
+
+                None => (),
+                Some(kind) => panic!("Unhandled kind {}", kind),
+            },
+            Op::Leaf(leaf) => parent.token_trees.push(leaf.clone().into()),
+            Op::Repeat { tokens, kind, separator } => {
+                let max = 10;
+                let cnt = match kind {
+                    RepeatKind::ZeroOrMore => rand(seed) % max,
+                    RepeatKind::OneOrMore => 1 + rand(seed) % max,
+                    RepeatKind::ZeroOrOne => rand(seed) % 2,
+                };
+                for i in 0..cnt {
+                    for it in tokens.iter() {
+                        collect_from_op(it, parent, seed);
+                    }
+                    if i + 1 != cnt {
+                        if let Some(sep) = separator {
+                            match sep {
+                                Separator::Literal(it) => parent
+                                    .token_trees
+                                    .push(tt::Leaf::Literal(it.clone().into()).into()),
+                                Separator::Ident(it) => parent
+                                    .token_trees
+                                    .push(tt::Leaf::Ident(it.clone().into()).into()),
+                                Separator::Puncts(puncts) => {
+                                    for it in puncts {
+                                        parent
+                                            .token_trees
+                                            .push(tt::Leaf::Punct(it.clone().into()).into())
+                                    }
+                                }
+                            };
+                        }
+                    }
+                }
+            }
+            Op::Subtree { tokens, delimiter } => {
+                let mut subtree =
+                    tt::Subtree { delimiter: delimiter.clone(), token_trees: Vec::new() };
+                tokens.iter().for_each(|it| {
+                    collect_from_op(it, &mut subtree, seed);
+                });
+                parent.token_trees.push(subtree.into());
+            }
+        };
+
+        // Simple linear congruential generator for determistic result
+        fn rand(seed: &mut usize) -> usize {
+            let a = 1664525;
+            let c = 1013904223;
+            *seed = usize::wrapping_add(usize::wrapping_mul(*seed, a), c);
+            return *seed;
+        };
+        fn make_ident(ident: &str) -> tt::TokenTree {
+            tt::Leaf::Ident(tt::Ident { id: tt::TokenId::unspecified(), text: SmolStr::new(ident) })
+                .into()
+        }
+        fn make_punct(char: char) -> tt::TokenTree {
+            tt::Leaf::Punct(tt::Punct {
+                id: tt::TokenId::unspecified(),
+                char,
+                spacing: tt::Spacing::Alone,
+            })
+            .into()
+        }
+        fn make_literal(lit: &str) -> tt::TokenTree {
+            tt::Leaf::Literal(tt::Literal {
+                id: tt::TokenId::unspecified(),
+                text: SmolStr::new(lit),
+            })
+            .into()
+        }
+        fn make_subtree(
+            kind: tt::DelimiterKind,
+            token_trees: Option<Vec<tt::TokenTree>>,
+        ) -> tt::TokenTree {
+            tt::Subtree {
+                delimiter: Some(tt::Delimiter { id: tt::TokenId::unspecified(), kind }),
+                token_trees: token_trees.unwrap_or_default(),
+            }
+            .into()
+        }
+    }
+}
diff --git a/crates/mbe/src/lib.rs b/crates/mbe/src/lib.rs
index d80bd7a33..6b4a4eb53 100644
--- a/crates/mbe/src/lib.rs
+++ b/crates/mbe/src/lib.rs
@@ -12,6 +12,9 @@ mod subtree_source;
 #[cfg(test)]
 mod tests;
 
+#[cfg(test)]
+mod benchmark;
+
 use std::fmt;
 
 use test_utils::mark;