From 49bfc6b555ca3be3084c0819391eabf2839e6f1b Mon Sep 17 00:00:00 2001
From: "Alex Lam S.L" <alexlamsl@gmail.com>
Date: Fri, 23 Mar 2018 03:43:52 +0800
Subject: [PATCH] improve performance (#3020)

- replace `find_if()` with `all()` wherever possible
- move ESTree-specific logic out of `figure_out_scope()`
---
 lib/compress.js      |  5 +++--
 lib/mozilla-ast.js   | 15 +++++++++++++++
 lib/parse.js         |  4 +++-
 lib/scope.js         | 23 -----------------------
 test/mocha/minify.js |  9 +++++++++
 5 files changed, 30 insertions(+), 26 deletions(-)

diff --git a/lib/compress.js b/lib/compress.js
index aeff904e..972341bb 100644
--- a/lib/compress.js
+++ b/lib/compress.js
@@ -3525,8 +3525,9 @@ merge(Compressor.prototype, {
                 var defs = [];
                 vars.each(function(def, name){
                     if (self instanceof AST_Lambda
-                        && find_if(function(x){ return x.name == def.name.name },
-                                   self.argnames)) {
+                        && !all(self.argnames, function(argname) {
+                            return argname.name != name;
+                        })) {
                         vars.del(name);
                     } else {
                         def = def.clone();
diff --git a/lib/mozilla-ast.js b/lib/mozilla-ast.js
index 8d7ee4b8..b80afbbb 100644
--- a/lib/mozilla-ast.js
+++ b/lib/mozilla-ast.js
@@ -564,6 +564,21 @@
         FROM_MOZ_STACK = [];
         var ast = from_moz(node);
         FROM_MOZ_STACK = save_stack;
+        ast.walk(new TreeWalker(function(node) {
+            if (node instanceof AST_LabelRef) {
+                for (var level = 0, parent; parent = this.parent(level); level++) {
+                    if (parent instanceof AST_Scope) break;
+                    if (parent instanceof AST_LabeledStatement && parent.label.name == node.name) {
+                        node.thedef = parent.label;
+                        break;
+                    }
+                }
+                if (!node.thedef) {
+                    var s = node.start;
+                    js_error("Undefined label " + node.name, s.file, s.line, s.col, s.pos);
+                }
+            }
+        }));
         return ast;
     };
 
diff --git a/lib/parse.js b/lib/parse.js
index af631149..f88d13ec 100644
--- a/lib/parse.js
+++ b/lib/parse.js
@@ -969,7 +969,9 @@ function parse($TEXT, options) {
 
     function labeled_statement() {
         var label = as_symbol(AST_Label);
-        if (find_if(function(l){ return l.name == label.name }, S.labels)) {
+        if (!all(S.labels, function(l) {
+            return l.name != label.name;
+        })) {
             // ECMA-262, 12.12: An ECMAScript program is considered
             // syntactically incorrect if it contains a
             // LabelledStatement that is enclosed by a
diff --git a/lib/scope.js b/lib/scope.js
index baa3e8bd..7cbd82c1 100644
--- a/lib/scope.js
+++ b/lib/scope.js
@@ -100,7 +100,6 @@ AST_Toplevel.DEFMETHOD("figure_out_scope", function(options){
     // pass 1: setup scope chaining and handle definitions
     var self = this;
     var scope = self.parent_scope = null;
-    var labels = new Dictionary();
     var defun = null;
     var tw = new TreeWalker(function(node, descend){
         if (node instanceof AST_Catch) {
@@ -115,25 +114,12 @@ AST_Toplevel.DEFMETHOD("figure_out_scope", function(options){
             node.init_scope_vars(scope);
             var save_scope = scope;
             var save_defun = defun;
-            var save_labels = labels;
             defun = scope = node;
-            labels = new Dictionary();
             descend();
             scope = save_scope;
             defun = save_defun;
-            labels = save_labels;
             return true;        // don't descend again in TreeWalker
         }
-        if (node instanceof AST_LabeledStatement) {
-            var l = node.label;
-            if (labels.has(l.name)) {
-                throw new Error(string_template("Label {name} defined twice", l));
-            }
-            labels.set(l.name, l);
-            descend();
-            labels.del(l.name);
-            return true;        // no descend again
-        }
         if (node instanceof AST_With) {
             for (var s = scope; s; s = s.parent_scope)
                 s.uses_with = true;
@@ -171,15 +157,6 @@ AST_Toplevel.DEFMETHOD("figure_out_scope", function(options){
         else if (node instanceof AST_SymbolCatch) {
             scope.def_variable(node).defun = defun;
         }
-        else if (node instanceof AST_LabelRef) {
-            var sym = labels.get(node.name);
-            if (!sym) throw new Error(string_template("Undefined label {name} [{line},{col}]", {
-                name: node.name,
-                line: node.start.line,
-                col: node.start.col
-            }));
-            node.thedef = sym;
-        }
     });
     self.walk(tw);
 
diff --git a/test/mocha/minify.js b/test/mocha/minify.js
index 02180a59..995897da 100644
--- a/test/mocha/minify.js
+++ b/test/mocha/minify.js
@@ -312,6 +312,15 @@ describe("minify", function() {
             assert.strictEqual(err.line, 1);
             assert.strictEqual(err.col, 12);
         });
+        it("should reject duplicated label name", function() {
+            var result = Uglify.minify("L:{L:{}}");
+            var err = result.error;
+            assert.ok(err instanceof Error);
+            assert.strictEqual(err.stack.split(/\n/)[0], "SyntaxError: Label L defined twice");
+            assert.strictEqual(err.filename, "0");
+            assert.strictEqual(err.line, 1);
+            assert.strictEqual(err.col, 4);
+        });
     });
 
     describe("global_defs", function() {
-- 
2.34.1