perf(es/minifier): Add has_flag to Comments (#8182)

crates/swc_common/src/comments.rs

@@ -84,6 +84,47 @@ pub trait Comments {
 
         ret
     }
+
+    /// This method is used to check if a comment with the given flag exist.
+    ///
+    /// If `flag` is `PURE`, this method will look for `@__PURE__` and
+    /// `#__PURE__`.
+    fn has_flag(&self, lo: BytePos, flag: &str) -> bool {
+        let cmts = self.take_leading(lo);
+
+        let ret = if let Some(comments) = &cmts {
+            (|| {
+                for c in comments {
+                    if c.kind == CommentKind::Block {
+                        for line in c.text.lines() {
+                            // jsdoc
+                            let line = line.trim_start_matches(['*', ' ']);
+                            let line = line.trim();
+
+                            //
+                            if line.len() == (flag.len() + 5)
+                                && (line.starts_with("#__") || line.starts_with("@__"))
+                                && line.ends_with("__")
+                                && flag == &line[3..line.len() - 2]
+                            {
+                                return true;
+                            }
+                        }
+                    }
+                }
+
+                false
+            })()
+        } else {
+            false
+        };
+
+        if let Some(cmts) = cmts {
+            self.add_trailing_comments(lo, cmts);
+        }
+
+        ret
+    }
 }
 
 macro_rules! delegate {
@@ -139,6 +180,10 @@ macro_rules! delegate {
         fn add_pure_comment(&self, pos: BytePos) {
             (**self).add_pure_comment(pos)
         }
+
+        fn has_flag(&self, lo: BytePos, flag: &str) -> bool {
+            (**self).has_flag(lo, flag)
+        }
     };
 }
 
@@ -225,6 +270,11 @@ impl Comments for NoopComments {
 
     #[cfg_attr(not(debug_assertions), inline(always))]
     fn add_pure_comment(&self, _: BytePos) {}
+
+    #[inline]
+    fn has_flag(&self, _: BytePos, _: &str) -> bool {
+        false
+    }
 }
 
 /// This implementation behaves like [NoopComments] if it's [None].
@@ -347,6 +397,15 @@ where
             f(&[])
         }
     }
+
+    #[inline]
+    fn has_flag(&self, lo: BytePos, flag: &str) -> bool {
+        if let Some(c) = self {
+            c.has_flag(lo, flag)
+        } else {
+            false
+        }
+    }
 }
 
 pub type SingleThreadedCommentsMapInner = FxHashMap<BytePos, Vec<Comment>>;
@@ -485,6 +544,31 @@ impl Comments for SingleThreadedComments {
             f(&[])
         }
     }
+
+    fn has_flag(&self, lo: BytePos, flag: &str) -> bool {
+        self.with_leading(lo, |comments| {
+            for c in comments {
+                if c.kind == CommentKind::Block {
+                    for line in c.text.lines() {
+                        // jsdoc
+                        let line = line.trim_start_matches(['*', ' ']);
+                        let line = line.trim();
+
+                        //
+                        if line.len() == (flag.len() + 5)
+                            && (line.starts_with("#__") || line.starts_with("@__"))
+                            && line.ends_with("__")
+                            && flag == &line[3..line.len() - 2]
+                        {
+                            return true;
+                        }
+                    }
+                }
+            }
+
+            false
+        })
+    }
 }
 
 impl SingleThreadedComments {

crates/swc_common/src/syntax_pos.rs

@@ -1139,11 +1139,17 @@ impl BytePos {
         self.0 >= Self::MIN_RESERVED.0 && self.0 != u32::MAX
     }
 
-    /// Returns true if this is synthesized and has no relevant input source
+    /// Returns `true`` if this is synthesized and has no relevant input source
     /// code.
     pub const fn is_dummy(self) -> bool {
         self.0 == 0
     }
+
+    /// Returns `true`` if this is explicitly synthesized or has relevant input
+    /// source so can have a comment.
+    pub const fn can_have_comment(self) -> bool {
+        self.0 != 0
+    }
 }
 
 /// A character offset. Because of multibyte utf8 characters, a byte offset

crates/swc_ecma_minifier/src/metadata/mod.rs

@@ -311,24 +311,5 @@ fn has_flag(comments: Option<&dyn Comments>, span: Span, text: &'static str) ->
         return false;
     }
 
-    find_comment(comments, span, |c| {
-        if c.kind == CommentKind::Block {
-            for line in c.text.lines() {
-                // jsdoc
-                let line = line.trim_start_matches(['*', ' ']);
-                let line = line.trim();
-
-                //
-                if line.len() == (text.len() + 5)
-                    && (line.starts_with("#__") || line.starts_with("@__"))
-                    && line.ends_with("__")
-                    && text == &line[3..line.len() - 2]
-                {
-                    return true;
-                }
-            }
-        }
-
-        false
-    })
+    comments.has_flag(span.lo, text)
 }

crates/swc_ecma_parser/tests/comments/exprs/array/blockStmt/input.js.span.swc-stderr

@@ -0,0 +1,119 @@
+
+  x Module
+   ,-[$DIR/tests/comments/exprs/array/blockStmt/input.js:1:1]
+ 1 | ,-> React.useEffect(() => {
+ 2 | |       // @refresh reset
+ 3 | `-> });
+   `----
+
+  x ModuleItem
+   ,-[$DIR/tests/comments/exprs/array/blockStmt/input.js:1:1]
+ 1 | ,-> React.useEffect(() => {
+ 2 | |       // @refresh reset
+ 3 | `-> });
+   `----
+
+  x Stmt
+   ,-[$DIR/tests/comments/exprs/array/blockStmt/input.js:1:1]
+ 1 | ,-> React.useEffect(() => {
+ 2 | |       // @refresh reset
+ 3 | `-> });
+   `----
+
+  x ExprStmt
+   ,-[$DIR/tests/comments/exprs/array/blockStmt/input.js:1:1]
+ 1 | ,-> React.useEffect(() => {
+ 2 | |       // @refresh reset
+ 3 | `-> });
+   `----
+
+  x Expr
+   ,-[$DIR/tests/comments/exprs/array/blockStmt/input.js:1:1]
+ 1 | ,-> React.useEffect(() => {
+ 2 | |       // @refresh reset
+ 3 | `-> });
+   `----
+
+  x CallExpr
+   ,-[$DIR/tests/comments/exprs/array/blockStmt/input.js:1:1]
+ 1 | ,-> React.useEffect(() => {
+ 2 | |       // @refresh reset
+ 3 | `-> });
+   `----
+
+  x Callee
+   ,-[$DIR/tests/comments/exprs/array/blockStmt/input.js:1:1]
+ 1 | React.useEffect(() => {
+   : ^^^^^^^^^^^^^^^
+ 2 |     // @refresh reset
+   `----
+
+  x Expr
+   ,-[$DIR/tests/comments/exprs/array/blockStmt/input.js:1:1]
+ 1 | React.useEffect(() => {
+   : ^^^^^^^^^^^^^^^
+ 2 |     // @refresh reset
+   `----
+
+  x MemberExpr
+   ,-[$DIR/tests/comments/exprs/array/blockStmt/input.js:1:1]
+ 1 | React.useEffect(() => {
+   : ^^^^^^^^^^^^^^^
+ 2 |     // @refresh reset
+   `----
+
+  x Expr
+   ,-[$DIR/tests/comments/exprs/array/blockStmt/input.js:1:1]
+ 1 | React.useEffect(() => {
+   : ^^^^^
+ 2 |     // @refresh reset
+   `----
+
+  x Ident
+   ,-[$DIR/tests/comments/exprs/array/blockStmt/input.js:1:1]
+ 1 | React.useEffect(() => {
+   : ^^^^^
+ 2 |     // @refresh reset
+   `----
+
+  x Ident
+   ,-[$DIR/tests/comments/exprs/array/blockStmt/input.js:1:1]
+ 1 | React.useEffect(() => {
+   :       ^^^^^^^^^
+ 2 |     // @refresh reset
+   `----
+
+  x ExprOrSpread
+   ,-[$DIR/tests/comments/exprs/array/blockStmt/input.js:1:1]
+ 1 | ,-> React.useEffect(() => {
+ 2 | |       // @refresh reset
+ 3 | `-> });
+   `----
+
+  x Expr
+   ,-[$DIR/tests/comments/exprs/array/blockStmt/input.js:1:1]
+ 1 | ,-> React.useEffect(() => {
+ 2 | |       // @refresh reset
+ 3 | `-> });
+   `----
+
+  x ArrowExpr
+   ,-[$DIR/tests/comments/exprs/array/blockStmt/input.js:1:1]
+ 1 | ,-> React.useEffect(() => {
+ 2 | |       // @refresh reset
+ 3 | `-> });
+   `----
+
+  x BlockStmtOrExpr
+   ,-[$DIR/tests/comments/exprs/array/blockStmt/input.js:1:1]
+ 1 | ,-> React.useEffect(() => {
+ 2 | |       // @refresh reset
+ 3 | `-> });
+   `----
+
+  x BlockStmt
+   ,-[$DIR/tests/comments/exprs/array/blockStmt/input.js:1:1]
+ 1 | ,-> React.useEffect(() => {
+ 2 | |       // @refresh reset
+ 3 | `-> });
+   `----

crates/swc_ecma_parser/tests/comments/exprs/call/simple/input.js.span.swc-stderr

@@ -0,0 +1,102 @@
+
+  x Module
+   ,-[$DIR/tests/comments/exprs/call/simple/input.js:1:1]
+ 1 | test(123/*post: 9*/, 456/*post: 10*/);
+   : ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   `----
+
+  x ModuleItem
+   ,-[$DIR/tests/comments/exprs/call/simple/input.js:1:1]
+ 1 | test(123/*post: 9*/, 456/*post: 10*/);
+   : ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   `----
+
+  x Stmt
+   ,-[$DIR/tests/comments/exprs/call/simple/input.js:1:1]
+ 1 | test(123/*post: 9*/, 456/*post: 10*/);
+   : ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   `----
+
+  x ExprStmt
+   ,-[$DIR/tests/comments/exprs/call/simple/input.js:1:1]
+ 1 | test(123/*post: 9*/, 456/*post: 10*/);
+   : ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   `----
+
+  x Expr
+   ,-[$DIR/tests/comments/exprs/call/simple/input.js:1:1]
+ 1 | test(123/*post: 9*/, 456/*post: 10*/);
+   : ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   `----
+
+  x CallExpr
+   ,-[$DIR/tests/comments/exprs/call/simple/input.js:1:1]
+ 1 | test(123/*post: 9*/, 456/*post: 10*/);
+   : ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   `----
+
+  x Callee
+   ,-[$DIR/tests/comments/exprs/call/simple/input.js:1:1]
+ 1 | test(123/*post: 9*/, 456/*post: 10*/);
+   : ^^^^
+   `----
+
+  x Expr
+   ,-[$DIR/tests/comments/exprs/call/simple/input.js:1:1]
+ 1 | test(123/*post: 9*/, 456/*post: 10*/);
+   : ^^^^
+   `----
+
+  x Ident
+   ,-[$DIR/tests/comments/exprs/call/simple/input.js:1:1]
+ 1 | test(123/*post: 9*/, 456/*post: 10*/);
+   : ^^^^
+   `----
+
+  x ExprOrSpread
+   ,-[$DIR/tests/comments/exprs/call/simple/input.js:1:1]
+ 1 | test(123/*post: 9*/, 456/*post: 10*/);
+   :      ^^^
+   `----
+
+  x Expr
+   ,-[$DIR/tests/comments/exprs/call/simple/input.js:1:1]
+ 1 | test(123/*post: 9*/, 456/*post: 10*/);
+   :      ^^^
+   `----
+
+  x Lit
+   ,-[$DIR/tests/comments/exprs/call/simple/input.js:1:1]
+ 1 | test(123/*post: 9*/, 456/*post: 10*/);
+   :      ^^^
+   `----
+
+  x Number
+   ,-[$DIR/tests/comments/exprs/call/simple/input.js:1:1]
+ 1 | test(123/*post: 9*/, 456/*post: 10*/);
+   :      ^^^
+   `----
+
+  x ExprOrSpread
+   ,-[$DIR/tests/comments/exprs/call/simple/input.js:1:1]
+ 1 | test(123/*post: 9*/, 456/*post: 10*/);
+   :                      ^^^
+   `----
+
+  x Expr
+   ,-[$DIR/tests/comments/exprs/call/simple/input.js:1:1]
+ 1 | test(123/*post: 9*/, 456/*post: 10*/);
+   :                      ^^^
+   `----
+
+  x Lit
+   ,-[$DIR/tests/comments/exprs/call/simple/input.js:1:1]
+ 1 | test(123/*post: 9*/, 456/*post: 10*/);
+   :                      ^^^
+   `----
+
+  x Number
+   ,-[$DIR/tests/comments/exprs/call/simple/input.js:1:1]
+ 1 | test(123/*post: 9*/, 456/*post: 10*/);
+   :                      ^^^
+   `----

crates/swc_ecma_parser/tests/comments/exprs/paren-annotations/1/input.js

@@ -0,0 +1,2 @@
+const fnB = /*#__NO_SIDE_EFFECTS__*/ (args) => {
+}