perf(parser): lazily build trivia map instead of build in-place (#903)

closes #898

crates/oxc_ast/src/lib.rs

@@ -22,7 +22,11 @@ mod visit_mut;
 pub use num_bigint::BigUint;
 
 pub use crate::{
-    ast_builder::AstBuilder, ast_kind::AstKind, trivia::Trivias, visit::Visit, visit_mut::VisitMut,
+    ast_builder::AstBuilder,
+    ast_kind::AstKind,
+    trivia::{Comment, CommentKind, Trivias, TriviasMap},
+    visit::Visit,
+    visit_mut::VisitMut,
 };
 
 // After experimenting with two types of boxed enum variants:

crates/oxc_ast/src/trivia.rs

@@ -4,16 +4,25 @@ use std::collections::BTreeMap;
 
 use oxc_span::Span;
 
+/// A vec of trivias from the lexer, tupled by (span.start, span.end).
+pub type Trivias = Vec<(u32, u32, CommentKind)>;
+
 /// Trivias such as comments
 ///
 /// Trivia (called that because it's trivial) represent the parts of the source text that are largely insignificant for normal understanding of the code.
 /// For example: whitespace, comments, and even conflict markers.
 #[derive(Debug, Default)]
-pub struct Trivias {
+pub struct TriviasMap {
     /// Keyed by span.start
     comments: BTreeMap<u32, Comment>,
 }
 
+impl From<Trivias> for TriviasMap {
+    fn from(trivias: Trivias) -> Self {
+        Self { comments: trivias.iter().map(|t| (t.0, Comment::new(t.1, t.2))).collect() }
+    }
+}
+
 /// Single or multiline comment
 #[derive(Debug, Clone, Copy)]
 #[allow(unused)]
@@ -46,7 +55,7 @@ impl Comment {
     }
 }
 
-impl Trivias {
+impl TriviasMap {
     pub fn comments(&self) -> &BTreeMap<u32, Comment> {
         &self.comments
     }

crates/oxc_linter/src/disable_directives.rs

@@ -1,4 +1,4 @@
-use oxc_ast::Trivias;
+use oxc_ast::TriviasMap;
 use oxc_span::Span;
 use rust_lapper::{Interval, Lapper};
 use rustc_hash::FxHashMap;
@@ -28,7 +28,7 @@ impl<'a> DisableDirectives<'a> {
 
 pub struct DisableDirectivesBuilder<'a, 'b> {
     source_text: &'a str,
-    trivias: &'b Trivias,
+    trivias: &'b TriviasMap,
     /// All the disabled rules with their corresponding covering spans
     intervals: Lapper<u32, DisabledRule<'a>>,
     /// Start of `eslint-disable`
@@ -38,7 +38,7 @@ pub struct DisableDirectivesBuilder<'a, 'b> {
 }
 
 impl<'a, 'b> DisableDirectivesBuilder<'a, 'b> {
-    pub fn new(source_text: &'a str, trivias: &'b Trivias) -> Self {
+    pub fn new(source_text: &'a str, trivias: &'b TriviasMap) -> Self {
         Self {
             source_text,
             trivias,

crates/oxc_parser/src/lexer/trivia_builder.rs

@@ -1,5 +1,4 @@
-use oxc_ast::Trivias;
+use oxc_ast::{CommentKind, Trivias};
-use oxc_span::Span;
 
 #[derive(Debug, Default)]
 pub struct TriviaBuilder {
@@ -11,13 +10,13 @@ impl TriviaBuilder {
         self.trivias
     }
 
+    /// skip leading `//`
     pub fn add_single_line_comment(&mut self, start: u32, end: u32) {
-        // skip leading `//`
+        self.trivias.push((start + 2, end, CommentKind::SingleLine));
-        self.trivias.add_single_line_comment(Span::new(start + 2, end));
     }
 
+    /// skip leading `/*` and trailing `*/`
     pub fn add_multi_line_comment(&mut self, start: u32, end: u32) {
-        // skip leading `/*` and trailing `*/`
+        self.trivias.push((start + 2, end - 2, CommentKind::MultiLine));
-        self.trivias.add_multi_line_comment(Span::new(start + 2, end - 2));
     }
 }

crates/oxc_semantic/src/builder.rs

@@ -4,7 +4,7 @@ use std::{cell::RefCell, path::PathBuf, rc::Rc, sync::Arc};
 
 use itertools::Itertools;
 #[allow(clippy::wildcard_imports)]
-use oxc_ast::{ast::*, AstKind, Trivias, Visit};
+use oxc_ast::{ast::*, AstKind, Trivias, TriviasMap, Visit};
 use oxc_diagnostics::Error;
 use oxc_span::{Atom, SourceType, Span};
 use oxc_syntax::{module_record::ModuleRecord, operator::AssignmentOperator};
@@ -40,7 +40,7 @@ pub struct SemanticBuilder<'a> {
 
     pub source_type: SourceType,
 
-    trivias: Rc<Trivias>,
+    trivias: Rc<TriviasMap>,
 
     /// Semantic early errors such as redeclaration errors.
     errors: RefCell<Vec<Error>>,
@@ -82,7 +82,7 @@ impl<'a> SemanticBuilder<'a> {
         let scope = ScopeTree::new(source_type);
         let current_scope_id = scope.root_scope_id();
 
-        let trivias = Rc::new(Trivias::default());
+        let trivias = Rc::new(TriviasMap::default());
         Self {
             source_text,
             source_type,
@@ -106,9 +106,8 @@ impl<'a> SemanticBuilder<'a> {
 
     #[must_use]
     pub fn with_trivias(mut self, trivias: Trivias) -> Self {
-        let trivias = Rc::new(trivias);
+        self.trivias = Rc::new(TriviasMap::from(trivias));
-        self.trivias = Rc::clone(&trivias);
+        self.jsdoc = JSDocBuilder::new(self.source_text, &self.trivias);
-        self.jsdoc = JSDocBuilder::new(self.source_text, &trivias);
         self
     }
 

crates/oxc_semantic/src/jsdoc/builder.rs

@@ -1,6 +1,6 @@
 use std::{collections::BTreeMap, rc::Rc};
 
-use oxc_ast::{AstKind, Trivias};
+use oxc_ast::{AstKind, TriviasMap};
 use oxc_span::{GetSpan, Span};
 
 use super::{JSDoc, JSDocComment};
@@ -8,13 +8,13 @@ use super::{JSDoc, JSDocComment};
 pub struct JSDocBuilder<'a> {
     source_text: &'a str,
 
-    trivias: Rc<Trivias>,
+    trivias: Rc<TriviasMap>,
 
     docs: BTreeMap<Span, JSDocComment<'a>>,
 }
 
 impl<'a> JSDocBuilder<'a> {
-    pub fn new(source_text: &'a str, trivias: &Rc<Trivias>) -> Self {
+    pub fn new(source_text: &'a str, trivias: &Rc<TriviasMap>) -> Self {
         Self { source_text, trivias: Rc::clone(trivias), docs: BTreeMap::default() }
     }
 

crates/oxc_semantic/src/lib.rs

@@ -13,7 +13,7 @@ use std::{rc::Rc, sync::Arc};
 
 pub use builder::{SemanticBuilder, SemanticBuilderReturn};
 pub use jsdoc::{JSDoc, JSDocComment, JSDocTag};
-use oxc_ast::{ast::IdentifierReference, AstKind, Trivias};
+use oxc_ast::{ast::IdentifierReference, AstKind, TriviasMap};
 use oxc_span::SourceType;
 pub use oxc_syntax::{
     module_record::ModuleRecord,
@@ -39,7 +39,7 @@ pub struct Semantic<'a> {
 
     symbols: SymbolTable,
 
-    trivias: Rc<Trivias>,
+    trivias: Rc<TriviasMap>,
 
     module_record: Arc<ModuleRecord>,
 
@@ -69,7 +69,7 @@ impl<'a> Semantic<'a> {
         &self.scopes
     }
 
-    pub fn trivias(&self) -> &Trivias {
+    pub fn trivias(&self) -> &TriviasMap {
         &self.trivias
     }