perf(es/minifier): Optimize MultiReplacer (#5977)

**Description:**

This PR splits the `MultiReplacer` into two variants. The first one is the cloning version, and this is parallel. The other one is the non-cloning version, which is not parallel.

crates/swc_ecma_minifier/src/compress/optimize/iife.rs

@@ -9,10 +9,7 @@ use swc_ecma_utils::{
 };
 use swc_ecma_visit::VisitMutWith;
 
-use super::{
+use super::{util::NormalMultiReplacer, Optimizer};
-    util::{MultiReplacer, MultiReplacerMode},
-    Optimizer,
-};
 #[cfg(feature = "debug")]
 use crate::debug::dump;
 use crate::{
@@ -323,16 +320,13 @@ where
     #[cfg_attr(feature = "debug", tracing::instrument(skip_all))]
     pub(super) fn inline_vars_in_node<N>(&mut self, n: &mut N, mut vars: FxHashMap<Id, Box<Expr>>)
     where
-        N: for<'aa> VisitMutWith<MultiReplacer<'aa>>,
+        N: for<'aa> VisitMutWith<NormalMultiReplacer<'aa>>,
     {
         trace_op!("inline: inline_vars_in_node");
 
-        n.visit_mut_with(&mut MultiReplacer::new(
+        let mut v = NormalMultiReplacer::new(&mut vars);
-            &mut vars,
+        n.visit_mut_with(&mut v);
-            false,
+        self.changed |= v.changed;
-            MultiReplacerMode::Normal,
-            &mut self.changed,
-        ));
     }
 
     /// Fully inlines iife.

crates/swc_ecma_minifier/src/compress/optimize/mod.rs

@@ -20,7 +20,7 @@ use Value::Known;
 
 use self::{
     unused::PropertyAccessOpts,
-    util::{extract_class_side_effect, MultiReplacer, MultiReplacerMode},
+    util::{extract_class_side_effect, CloningMultiReplacer, NormalMultiReplacer},
 };
 use super::util::{drop_invalid_stmts, is_fine_for_if_cons};
 #[cfg(feature = "debug")]
@@ -262,34 +262,24 @@ impl Vars {
     /// Returns true if something is changed.
     fn inline_with_multi_replacer<N>(&mut self, n: &mut N) -> bool
     where
-        N: for<'aa> VisitMutWith<MultiReplacer<'aa>>,
+        N: for<'aa> VisitMutWith<NormalMultiReplacer<'aa>>,
+        N: for<'aa> VisitMutWith<CloningMultiReplacer<'aa>>,
     {
         let mut changed = false;
-        if !self.simple_functions.is_empty() {
+        if !self.simple_functions.is_empty() || !self.lits_for_cmp.is_empty() {
-            n.visit_mut_with(&mut MultiReplacer::new(
+            let mut v = CloningMultiReplacer {
-                &mut self.simple_functions,
+                lits_for_cmp: &self.lits_for_cmp,
-                true,
+                simple_functions: &self.simple_functions,
-                MultiReplacerMode::OnlyCallee,
+                changed: false,
-                &mut changed,
+            };
-            ));
+            n.visit_mut_with(&mut v);
-        }
+            changed |= v.changed;
-
-        if !self.lits_for_cmp.is_empty() {
-            n.visit_mut_with(&mut MultiReplacer::new(
-                &mut self.lits_for_cmp,
-                true,
-                MultiReplacerMode::OnlyComparisonWithLit,
-                &mut changed,
-            ));
         }
 
         if !self.vars_for_inlining.is_empty() {
-            n.visit_mut_with(&mut MultiReplacer::new(
+            let mut v = NormalMultiReplacer::new(&mut self.vars_for_inlining);
-                &mut self.vars_for_inlining,
+            n.visit_mut_with(&mut v);
-                false,
+            changed |= v.changed;
-                MultiReplacerMode::Normal,
-                &mut changed,
-            ));
         }
 
         changed

crates/swc_ecma_minifier/src/compress/optimize/util.rs

@@ -4,12 +4,13 @@ use rustc_hash::FxHashMap;
 use swc_atoms::js_word;
 use swc_common::{Span, SyntaxContext, DUMMY_SP};
 use swc_ecma_ast::*;
+use swc_ecma_transforms_base::perf::{Parallel, ParallelExt};
 use swc_ecma_utils::{ExprCtx, ExprExt};
 use swc_ecma_visit::{noop_visit_mut_type, VisitMut, VisitMutWith};
 use tracing::debug;
 
 use super::{Ctx, Optimizer};
-use crate::mode::Mode;
+use crate::{mode::Mode, HEAVY_TASK_PARALLELS};
 
 impl<'b, M> Optimizer<'b, M>
 where
@@ -156,43 +157,28 @@ impl VisitMut for Remapper {
     }
 }
 
-pub(crate) struct MultiReplacer<'a> {
+#[derive(Clone, Copy)]
-    vars: &'a mut FxHashMap<Id, Box<Expr>>,
+pub(crate) struct CloningMultiReplacer<'a> {
-    clone: bool,
+    pub simple_functions: &'a FxHashMap<Id, Box<Expr>>,
-    mode: MultiReplacerMode,
+    pub lits_for_cmp: &'a FxHashMap<Id, Box<Expr>>,
-    worked: &'a mut bool,
+    pub changed: bool,
 }
 
-#[repr(u8)]
+impl Parallel for CloningMultiReplacer<'_> {
-#[derive(Debug, Clone, Copy)]
+    fn create(&self) -> Self {
-
+        *self
-pub enum MultiReplacerMode {
-    Normal,
-    OnlyCallee,
-    OnlyComparisonWithLit,
-}
-
-impl<'a> MultiReplacer<'a> {
-    /// `worked` will be changed to `true` if any replacement is done
-    pub fn new(
-        vars: &'a mut FxHashMap<Id, Box<Expr>>,
-        clone: bool,
-        mode: MultiReplacerMode,
-        worked: &'a mut bool,
-    ) -> Self {
-        MultiReplacer {
-            vars,
-            clone,
-            mode,
-            worked,
-        }
     }
 
-    fn var(&mut self, i: &Id) -> Option<Box<Expr>> {
+    fn merge(&mut self, other: Self) {
-        let mut e = if self.clone {
+        self.changed |= other.changed;
-            self.vars.get(i).cloned()?
+    }
-        } else {
+}
-            self.vars.remove(i)?
+
+impl<'a> CloningMultiReplacer<'a> {
+    fn var(&mut self, i: &Id, mode: MultiReplacerMode) -> Option<Box<Expr>> {
+        let mut e = match mode {
+            MultiReplacerMode::OnlyCallee => self.simple_functions.get(i).cloned()?,
+            MultiReplacerMode::OnlyComparisonWithLit => self.lits_for_cmp.get(i).cloned()?,
         };
 
         e.visit_mut_children_with(self);
@@ -209,11 +195,11 @@ impl<'a> MultiReplacer<'a> {
         }
     }
 
-    fn check(&mut self, e: &mut Expr) {
+    fn check(&mut self, e: &mut Expr, mode: MultiReplacerMode) {
         if let Expr::Ident(i) = e {
-            if let Some(new) = self.var(&i.to_id()) {
+            if let Some(new) = self.var(&i.to_id(), mode) {
                 debug!("multi-replacer: Replaced `{}`", i);
-                *self.worked = true;
+                self.changed = true;
 
                 *e = *new;
             }
@@ -221,37 +207,111 @@ impl<'a> MultiReplacer<'a> {
     }
 }
 
-impl VisitMut for MultiReplacer<'_> {
+#[derive(Debug, Clone, Copy)]
+enum MultiReplacerMode {
+    OnlyCallee,
+    OnlyComparisonWithLit,
+}
+
+impl VisitMut for CloningMultiReplacer<'_> {
     noop_visit_mut_type!();
 
     fn visit_mut_callee(&mut self, e: &mut Callee) {
         e.visit_mut_children_with(self);
 
-        if matches!(self.mode, MultiReplacerMode::OnlyCallee) {
+        if let Callee::Expr(e) = e {
-            if let Callee::Expr(e) = e {
+            self.check(e, MultiReplacerMode::OnlyCallee);
-                self.check(e);
-            }
         }
     }
 
     fn visit_mut_bin_expr(&mut self, e: &mut BinExpr) {
         e.visit_mut_children_with(self);
 
-        if let MultiReplacerMode::OnlyComparisonWithLit = self.mode {
+        match e.op {
-            match e.op {
+            op!("===") | op!("!==") | op!("==") | op!("!=") => {
-                op!("===") | op!("!==") | op!("==") | op!("!=") => {
+                //
-                    //
+                if e.left.is_lit() {
-                    if e.left.is_lit() {
+                    self.check(&mut e.right, MultiReplacerMode::OnlyComparisonWithLit);
-                        self.check(&mut e.right);
+                } else if e.right.is_lit() {
-                    } else if e.right.is_lit() {
+                    self.check(&mut e.left, MultiReplacerMode::OnlyComparisonWithLit);
-                        self.check(&mut e.left);
-                    }
                 }
-                _ => {}
             }
+            _ => {}
         }
     }
 
+    fn visit_mut_prop_or_spreads(&mut self, n: &mut Vec<PropOrSpread>) {
+        self.maybe_par(*HEAVY_TASK_PARALLELS, n, |v, n| {
+            n.visit_mut_with(v);
+        });
+    }
+
+    fn visit_mut_expr_or_spreads(&mut self, n: &mut Vec<ExprOrSpread>) {
+        self.maybe_par(*HEAVY_TASK_PARALLELS, n, |v, n| {
+            n.visit_mut_with(v);
+        });
+    }
+
+    fn visit_mut_opt_vec_expr_or_spreads(&mut self, n: &mut Vec<Option<ExprOrSpread>>) {
+        self.maybe_par(*HEAVY_TASK_PARALLELS, n, |v, n| {
+            n.visit_mut_with(v);
+        });
+    }
+
+    fn visit_mut_exprs(&mut self, n: &mut Vec<Box<Expr>>) {
+        self.maybe_par(*HEAVY_TASK_PARALLELS, n, |v, n| {
+            n.visit_mut_with(v);
+        });
+    }
+
+    fn visit_mut_stmts(&mut self, n: &mut Vec<Stmt>) {
+        self.maybe_par(*HEAVY_TASK_PARALLELS, n, |v, n| {
+            n.visit_mut_with(v);
+        });
+    }
+
+    fn visit_mut_module_items(&mut self, n: &mut Vec<ModuleItem>) {
+        self.maybe_par(*HEAVY_TASK_PARALLELS, n, |v, n| {
+            n.visit_mut_with(v);
+        });
+    }
+}
+
+pub(crate) struct NormalMultiReplacer<'a> {
+    pub vars: &'a mut FxHashMap<Id, Box<Expr>>,
+    pub changed: bool,
+}
+
+impl<'a> NormalMultiReplacer<'a> {
+    /// `worked` will be changed to `true` if any replacement is done
+    pub fn new(vars: &'a mut FxHashMap<Id, Box<Expr>>) -> Self {
+        NormalMultiReplacer {
+            vars,
+            changed: false,
+        }
+    }
+
+    fn var(&mut self, i: &Id) -> Option<Box<Expr>> {
+        let mut e = self.vars.remove(i)?;
+
+        e.visit_mut_children_with(self);
+
+        match &*e {
+            Expr::Ident(Ident {
+                sym: js_word!("eval"),
+                ..
+            }) => Some(Box::new(Expr::Seq(SeqExpr {
+                span: DUMMY_SP,
+                exprs: vec![0.into(), e],
+            }))),
+            _ => Some(e),
+        }
+    }
+}
+
+impl VisitMut for NormalMultiReplacer<'_> {
+    noop_visit_mut_type!();
+
     fn visit_mut_expr(&mut self, e: &mut Expr) {
         if self.vars.is_empty() {
             return;
@@ -262,14 +322,12 @@ impl VisitMut for MultiReplacer<'_> {
             return;
         }
 
-        if matches!(self.mode, MultiReplacerMode::Normal) {
+        if let Expr::Ident(i) = e {
-            if let Expr::Ident(i) = e {
+            if let Some(new) = self.var(&i.to_id()) {
-                if let Some(new) = self.var(&i.to_id()) {
+                debug!("multi-replacer: Replaced `{}`", i);
-                    debug!("multi-replacer: Replaced `{}`", i);
+                self.changed = true;
-                    *self.worked = true;
 
-                    *e = *new;
+                *e = *new;
-                }
             }
         }
     }
@@ -290,20 +348,18 @@ impl VisitMut for MultiReplacer<'_> {
     fn visit_mut_prop(&mut self, p: &mut Prop) {
         p.visit_mut_children_with(self);
 
-        if matches!(self.mode, MultiReplacerMode::Normal) {
+        if let Prop::Shorthand(i) = p {
-            if let Prop::Shorthand(i) = p {
+            if let Some(value) = self.var(&i.to_id()) {
-                if let Some(value) = self.var(&i.to_id()) {
+                debug!("multi-replacer: Replaced `{}` as shorthand", i);
-                    debug!("multi-replacer: Replaced `{}` as shorthand", i);
+                self.changed = true;
-                    *self.worked = true;
 
-                    *p = Prop::KeyValue(KeyValueProp {
+                *p = Prop::KeyValue(KeyValueProp {
-                        key: PropName::Ident(Ident::new(
+                    key: PropName::Ident(Ident::new(
-                            i.sym.clone(),
+                        i.sym.clone(),
-                            i.span.with_ctxt(Default::default()),
+                        i.span.with_ctxt(Default::default()),
-                        )),
+                    )),
-                        value,
+                    value,
-                    });
+                });
-                }
             }
         }
     }