feat(parser,codegen)!: parse and print#__NO_SIDE_EFFECTS__ (#9496)

Co-authored-by: Boshen <1430279+Boshen@users.noreply.github.com>
oxc-project · Mar 3, 2025 · a8d1d48 · a8d1d48
1 parent 7fde233
commit a8d1d48
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Showing 22 changed files with 281 additions and 180 deletions.
diff --git a/crates/oxc_ast/src/ast/comment.rs b/crates/oxc_ast/src/ast/comment.rs
@@ -125,17 +125,6 @@ impl Comment {
             || source_text.contains("@preserve")
     }
 
-    /// `#__PURE__` Notation Specification
-    ///
-    /// <https://github.com/javascript-compiler-hints/compiler-notations-spec/blob/c14f7e197cb225c9eee877143536665ce3150712/pure-notation-spec.md>
-    #[inline] // inline because code path is hot.
-    pub fn is_pure(&self, source_text: &str) -> bool {
-        source_text[(self.span.start + 2) as usize..]
-            .trim_ascii_start()
-            .strip_prefix(['@', '#'])
-            .is_some_and(|s| s.starts_with("__PURE__"))
-    }
-
     /// Gets the span of the comment content.
     pub fn content_span(&self) -> Span {
         match self.kind {

diff --git a/crates/oxc_ast/src/ast/js.rs b/crates/oxc_ast/src/ast/js.rs
@@ -1834,6 +1834,10 @@ pub struct ArrowFunctionExpression<'a> {
     #[estree(via = ArrowFunctionExpressionBody)]
     pub body: Box<'a, FunctionBody<'a>>,
     pub scope_id: Cell<Option<ScopeId>>,
+    /// `true` if the function is marked with a `/*#__NO_SIDE_EFFECTS__*/` comment
+    #[builder(default)]
+    #[estree(skip)]
+    pub pure: bool,
 }
 
 /// Generator Function Definitions

diff --git a/crates/oxc_ast/src/generated/assert_layouts.rs b/crates/oxc_ast/src/generated/assert_layouts.rs
@@ -555,6 +555,7 @@ const _: () = {
     assert!(offset_of!(ArrowFunctionExpression, return_type) == 32);
     assert!(offset_of!(ArrowFunctionExpression, body) == 40);
     assert!(offset_of!(ArrowFunctionExpression, scope_id) == 48);
+    assert!(offset_of!(ArrowFunctionExpression, pure) == 52);
 
     assert!(size_of::<YieldExpression>() == 32);
     assert!(align_of::<YieldExpression>() == 8);
@@ -1943,7 +1944,7 @@ const _: () = {
     assert!(offset_of!(FunctionBody, directives) == 8);
     assert!(offset_of!(FunctionBody, statements) == 24);
 
-    assert!(size_of::<ArrowFunctionExpression>() == 32);
+    assert!(size_of::<ArrowFunctionExpression>() == 36);
     assert!(align_of::<ArrowFunctionExpression>() == 4);
     assert!(offset_of!(ArrowFunctionExpression, span) == 0);
     assert!(offset_of!(ArrowFunctionExpression, expression) == 8);
@@ -1953,6 +1954,7 @@ const _: () = {
     assert!(offset_of!(ArrowFunctionExpression, return_type) == 20);
     assert!(offset_of!(ArrowFunctionExpression, body) == 24);
     assert!(offset_of!(ArrowFunctionExpression, scope_id) == 28);
+    assert!(offset_of!(ArrowFunctionExpression, pure) == 32);
 
     assert!(size_of::<YieldExpression>() == 20);
     assert!(align_of::<YieldExpression>() == 4);

diff --git a/crates/oxc_ast/src/generated/ast_builder.rs b/crates/oxc_ast/src/generated/ast_builder.rs
@@ -5589,6 +5589,7 @@ impl<'a> AstBuilder<'a> {
             return_type: return_type.into_in(self.allocator),
             body: body.into_in(self.allocator),
             scope_id: Default::default(),
+            pure: Default::default(),
         }
     }
 
@@ -5635,9 +5636,9 @@ impl<'a> AstBuilder<'a> {
         )
     }
 
-    /// Build an [`ArrowFunctionExpression`] with `scope_id`.
+    /// Build an [`ArrowFunctionExpression`] with `scope_id` and `pure`.
     ///
-    /// If you want the built node to be allocated in the memory arena, use [`AstBuilder::alloc_arrow_function_expression_with_scope_id`] instead.
+    /// If you want the built node to be allocated in the memory arena, use [`AstBuilder::alloc_arrow_function_expression_with_scope_id_and_pure`] instead.
     ///
     /// ## Parameters
     /// * `span`: The [`Span`] covering this node
@@ -5648,8 +5649,9 @@ impl<'a> AstBuilder<'a> {
     /// * `return_type`
     /// * `body`: See `expression` for whether this arrow expression returns an expression.
     /// * `scope_id`
+    /// * `pure`: `true` if the function is marked with a `/*#__NO_SIDE_EFFECTS__*/` comment
     #[inline]
-    pub fn arrow_function_expression_with_scope_id<T1, T2, T3, T4>(
+    pub fn arrow_function_expression_with_scope_id_and_pure<T1, T2, T3, T4>(
         self,
         span: Span,
         expression: bool,
@@ -5659,6 +5661,7 @@ impl<'a> AstBuilder<'a> {
         return_type: T3,
         body: T4,
         scope_id: ScopeId,
+        pure: bool,
     ) -> ArrowFunctionExpression<'a>
     where
         T1: IntoIn<'a, Option<Box<'a, TSTypeParameterDeclaration<'a>>>>,
@@ -5675,12 +5678,13 @@ impl<'a> AstBuilder<'a> {
             return_type: return_type.into_in(self.allocator),
             body: body.into_in(self.allocator),
             scope_id: Cell::new(Some(scope_id)),
+            pure,
         }
     }
 
-    /// Build an [`ArrowFunctionExpression`] with `scope_id`, and store it in the memory arena.
+    /// Build an [`ArrowFunctionExpression`] with `scope_id` and `pure`, and store it in the memory arena.
     ///
-    /// Returns a [`Box`] containing the newly-allocated node. If you want a stack-allocated node, use [`AstBuilder::arrow_function_expression_with_scope_id`] instead.
+    /// Returns a [`Box`] containing the newly-allocated node. If you want a stack-allocated node, use [`AstBuilder::arrow_function_expression_with_scope_id_and_pure`] instead.
     ///
     /// ## Parameters
     /// * `span`: The [`Span`] covering this node
@@ -5691,8 +5695,9 @@ impl<'a> AstBuilder<'a> {
     /// * `return_type`
     /// * `body`: See `expression` for whether this arrow expression returns an expression.
     /// * `scope_id`
+    /// * `pure`: `true` if the function is marked with a `/*#__NO_SIDE_EFFECTS__*/` comment
     #[inline]
-    pub fn alloc_arrow_function_expression_with_scope_id<T1, T2, T3, T4>(
+    pub fn alloc_arrow_function_expression_with_scope_id_and_pure<T1, T2, T3, T4>(
         self,
         span: Span,
         expression: bool,
@@ -5702,6 +5707,7 @@ impl<'a> AstBuilder<'a> {
         return_type: T3,
         body: T4,
         scope_id: ScopeId,
+        pure: bool,
     ) -> Box<'a, ArrowFunctionExpression<'a>>
     where
         T1: IntoIn<'a, Option<Box<'a, TSTypeParameterDeclaration<'a>>>>,
@@ -5710,7 +5716,7 @@ impl<'a> AstBuilder<'a> {
         T4: IntoIn<'a, Box<'a, FunctionBody<'a>>>,
     {
         Box::new_in(
-            self.arrow_function_expression_with_scope_id(
+            self.arrow_function_expression_with_scope_id_and_pure(
                 span,
                 expression,
                 r#async,
@@ -5719,6 +5725,7 @@ impl<'a> AstBuilder<'a> {
                 return_type,
                 body,
                 scope_id,
+                pure,
             ),
             self.allocator,
         )

diff --git a/crates/oxc_ast/src/generated/derive_clone_in.rs b/crates/oxc_ast/src/generated/derive_clone_in.rs
@@ -1923,6 +1923,7 @@ impl<'new_alloc> CloneIn<'new_alloc> for ArrowFunctionExpression<'_> {
             return_type: CloneIn::clone_in(&self.return_type, allocator),
             body: CloneIn::clone_in(&self.body, allocator),
             scope_id: Default::default(),
+            pure: CloneIn::clone_in(&self.pure, allocator),
         }
     }
 }

diff --git a/crates/oxc_ast/src/generated/derive_content_eq.rs b/crates/oxc_ast/src/generated/derive_content_eq.rs
@@ -1117,6 +1117,7 @@ impl ContentEq for ArrowFunctionExpression<'_> {
             && ContentEq::content_eq(&self.params, &other.params)
             && ContentEq::content_eq(&self.return_type, &other.return_type)
             && ContentEq::content_eq(&self.body, &other.body)
+            && ContentEq::content_eq(&self.pure, &other.pure)
     }
 }
 

diff --git a/crates/oxc_codegen/src/comment.rs b/crates/oxc_codegen/src/comment.rs
@@ -18,19 +18,10 @@ impl Codegen<'_> {
         self.comments.contains_key(&start)
     }
 
-    pub(crate) fn has_annotation_comment(&self, start: u32) -> bool {
-        if !self.options.print_annotation_comments() {
-            return false;
-        }
-        self.comments.get(&start).is_some_and(|comments| {
-            comments.iter().any(|comment| self.is_annotation_comment(comment))
-        })
-    }
-
     pub(crate) fn has_non_annotation_comment(&self, start: u32) -> bool {
         if self.options.print_annotation_comments() {
             self.comments.get(&start).is_some_and(|comments| {
-                comments.iter().any(|comment| !self.is_annotation_comment(comment))
+                comments.iter().any(|comment| !self.is_pure_comment(comment))
             })
         } else {
             self.has_comment(start)
@@ -40,7 +31,7 @@ impl Codegen<'_> {
     /// `#__PURE__` Notation Specification
     ///
     /// <https://github.com/javascript-compiler-hints/compiler-notations-spec/blob/c14f7e197cb225c9eee877143536665ce3150712/pure-notation-spec.md>
-    fn is_annotation_comment(&self, comment: &Comment) -> bool {
+    fn is_pure_comment(&self, comment: &Comment) -> bool {
         let s = comment.content_span().source_text(self.source_text).trim_start();
         if let Some(s) = s.strip_prefix(['@', '#']) {
             s.starts_with("__PURE__") || s.starts_with("__NO_SIDE_EFFECTS__")
@@ -52,8 +43,7 @@ impl Codegen<'_> {
     /// Whether to keep leading comments.
     fn is_leading_comments(&self, comment: &Comment) -> bool {
         comment.preceded_by_newline
-            && (comment.is_jsdoc(self.source_text)
-                || (comment.is_line() && self.is_annotation_comment(comment)))
+            && (comment.is_jsdoc(self.source_text) && !self.is_pure_comment(comment))
             && !comment.content_span().source_text(self.source_text).chars().all(|c| c == '*')
         // webpack comment `/*****/`
     }
@@ -118,36 +108,11 @@ impl Codegen<'_> {
         }
     }
 
-    pub(crate) fn print_annotation_comments(&mut self, node_start: u32) {
-        if !self.options.print_annotation_comments() {
-            return;
-        }
-
-        // If there is has annotation comments awaiting move to here, print them.
-        let start = self.start_of_annotation_comment.take().unwrap_or(node_start);
-
-        let Some(comments) = self.comments.remove(&start) else { return };
-
-        for comment in comments {
-            if !self.is_annotation_comment(&comment) {
-                continue;
-            }
-            if comment.is_line() {
-                self.print_str("/*");
-                self.print_str(comment.content_span().source_text(self.source_text));
-                self.print_str("*/");
-            } else {
-                self.print_str(comment.span.source_text(self.source_text));
-            }
-            self.print_hard_space();
-        }
-    }
-
     pub(crate) fn print_expr_comments(&mut self, start: u32) -> bool {
         let Some(comments) = self.comments.remove(&start) else { return false };
 
         let (annotation_comments, comments): (Vec<_>, Vec<_>) =
-            comments.into_iter().partition(|comment| self.is_annotation_comment(comment));
+            comments.into_iter().partition(|comment| self.is_pure_comment(comment));
 
         if !annotation_comments.is_empty() {
             self.comments.insert(start, annotation_comments);