v2.8.23

- deep cloning of `AST_LabeledStatement`
- `L:do{...}while(false)`
- empty statement with label within block

extend `test/ufuzz.js`
- generate labels for blocks & loops
- generate for-in statements
- skip suspicious option search if `minify()` errs

fixes #1833

lib/ast.js

@@ -214,12 +214,13 @@ var AST_LabeledStatement = DEFNODE("LabeledStatement", "label", {
     clone: function(deep) {
         var node = this._clone(deep);
         if (deep) {
-            var refs = node.label.references;
+            var label = node.label;
-            var label = this.label;
+            var def = this.label;
             node.walk(new TreeWalker(function(node) {
                 if (node instanceof AST_LoopControl
-                    && node.label && node.label.thedef === label) {
+                    && node.label && node.label.thedef === def) {
-                    refs.push(node);
+                    node.label.thedef = label;
+                    label.references.push(node);
                 }
             }));
         }

lib/compress.js

@@ -271,6 +271,14 @@ merge(Compressor.prototype, {
                     if (d.fixed === undefined || !is_safe(d)
                         || is_modified(node, 0, node.fixed_value() instanceof AST_Lambda)) {
                         d.fixed = false;
+                    } else {
+                        var parent = tw.parent();
+                        if (parent instanceof AST_Assign && parent.operator == "=" && node === parent.right
+                            || parent instanceof AST_Call && node !== parent.expression
+                            || parent instanceof AST_Return && node === parent.value && node.scope !== d.scope
+                            || parent instanceof AST_VarDef && node === parent.value) {
+                            d.escaped = true;
+                        }
                     }
                 }
                 if (node instanceof AST_SymbolCatch) {
@@ -359,7 +367,19 @@ merge(Compressor.prototype, {
                     pop();
                     return true;
                 }
-                if (node instanceof AST_Catch || node instanceof AST_SwitchBranch) {
+                if (node instanceof AST_Try) {
+                    push();
+                    walk_body(node, tw);
+                    pop();
+                    if (node.bcatch) {
+                        push();
+                        node.bcatch.walk(tw);
+                        pop();
+                    }
+                    if (node.bfinally) node.bfinally.walk(tw);
+                    return true;
+                }
+                if (node instanceof AST_SwitchBranch) {
                     push();
                     descend();
                     pop();
@@ -393,6 +413,7 @@ merge(Compressor.prototype, {
         }
 
         function reset_def(def) {
+            def.escaped = false;
             if (toplevel || !def.global || def.orig[0] instanceof AST_SymbolConst) {
                 def.fixed = undefined;
             } else {
@@ -1549,23 +1570,20 @@ merge(Compressor.prototype, {
                 : ev(this.alternative, compressor);
         });
         def(AST_SymbolRef, function(compressor){
-            if (this._evaluating) throw def;
+            if (!compressor.option("reduce_vars") || this._evaluating) throw def;
             this._evaluating = true;
             try {
                 var fixed = this.fixed_value();
-                if (compressor.option("reduce_vars") && fixed) {
+                if (!fixed) throw def;
-                    if (compressor.option("unsafe")) {
+                var value = ev(fixed, compressor);
-                        if (!HOP(fixed, "_evaluated")) {
+                if (!HOP(fixed, "_eval")) fixed._eval = function() {
-                            fixed._evaluated = ev(fixed, compressor);
+                    return value;
-                        }
+                };
-                        return fixed._evaluated;
+                if (value && typeof value == "object" && this.definition().escaped) throw def;
-                    }
+                return value;
-                    return ev(fixed, compressor);
-                }
             } finally {
                 this._evaluating = false;
             }
-            throw def;
         });
         def(AST_PropAccess, function(compressor){
             if (compressor.option("unsafe")) {
@@ -1980,7 +1998,7 @@ merge(Compressor.prototype, {
                         }
                         return node;
                     }
-                    if (drop_vars && node instanceof AST_Definitions && !(tt.parent() instanceof AST_ForIn)) {
+                    if (drop_vars && node instanceof AST_Definitions && !(tt.parent() instanceof AST_ForIn && tt.parent().init === node)) {
                         var def = node.definitions.filter(function(def){
                             if (def.value) def.value = def.value.transform(tt);
                             var sym = def.name.definition();
@@ -2058,26 +2076,32 @@ merge(Compressor.prototype, {
                             return maintain_this_binding(tt.parent(), node, node.right.transform(tt));
                         }
                     }
+                    // certain combination of unused name + side effect leads to:
+                    //    https://github.com/mishoo/UglifyJS2/issues/44
+                    //    https://github.com/mishoo/UglifyJS2/issues/1830
+                    // that's an invalid AST.
+                    // We fix it at this stage by moving the `var` outside the `for`.
                     if (node instanceof AST_For) {
                         descend(node, this);
-
                         if (node.init instanceof AST_BlockStatement) {
-                            // certain combination of unused name + side effect leads to:
+                            var block = node.init;
-                            //    https://github.com/mishoo/UglifyJS2/issues/44
+                            node.init = block.body.pop();
-                            // that's an invalid AST.
+                            block.body.push(node);
-                            // We fix it at this stage by moving the `var` outside the `for`.
+                            return in_list ? MAP.splice(block.body) : block;
-
-                            var body = node.init.body.slice(0, -1);
-                            node.init = node.init.body.slice(-1)[0].body;
-                            body.push(node);
-
-                            return in_list ? MAP.splice(body) : make_node(AST_BlockStatement, node, {
-                                body: body
-                            });
                         } else if (is_empty(node.init)) {
                             node.init = null;
-                            return node;
                         }
+                        return node;
+                    }
+                    if (node instanceof AST_LabeledStatement && node.body instanceof AST_For) {
+                        descend(node, this);
+                        if (node.body instanceof AST_BlockStatement) {
+                            var block = node.body;
+                            node.body = block.body.pop();
+                            block.body.push(node);
+                            return in_list ? MAP.splice(block.body) : block;
+                        }
+                        return node;
                     }
                     if (node instanceof AST_Scope && node !== self)
                         return node;
@@ -2380,7 +2404,7 @@ merge(Compressor.prototype, {
             if (compressor.option("dead_code") && self instanceof AST_While) {
                 var a = [];
                 extract_declarations_from_unreachable_code(compressor, self.body, a);
-                return make_node(AST_BlockStatement, self, { body: a });
+                return make_node(AST_BlockStatement, self, { body: a }).optimize(compressor);
             }
             if (self instanceof AST_Do) {
                 var has_loop_control = false;
@@ -2389,7 +2413,8 @@ merge(Compressor.prototype, {
                     if (node instanceof AST_LoopControl && tw.loopcontrol_target(node) === self)
                         return has_loop_control = true;
                 });
-                self.walk(tw);
+                var parent = compressor.parent();
+                (parent instanceof AST_LabeledStatement ? parent : self).walk(tw);
                 if (!has_loop_control) return self.body;
             }
         }
@@ -2459,7 +2484,7 @@ merge(Compressor.prototype, {
                     }));
                 }
                 extract_declarations_from_unreachable_code(compressor, self.body, a);
-                return make_node(AST_BlockStatement, self, { body: a });
+                return make_node(AST_BlockStatement, self, { body: a }).optimize(compressor);
             }
             if (cond !== self.condition) {
                 cond = make_node_from_constant(cond, self.condition).transform(compressor);
@@ -2711,9 +2736,9 @@ merge(Compressor.prototype, {
             var body = [];
             if (self.bcatch) extract_declarations_from_unreachable_code(compressor, self.bcatch, body);
             if (self.bfinally) body = body.concat(self.bfinally.body);
-            return body.length > 0 ? make_node(AST_BlockStatement, self, {
+            return make_node(AST_BlockStatement, self, {
                 body: body
-            }).optimize(compressor) : make_node(AST_EmptyStatement, self);
+            }).optimize(compressor);
         }
         return self;
     });
@@ -3595,7 +3620,9 @@ merge(Compressor.prototype, {
                 return make_node(AST_Infinity, self).optimize(compressor);
             }
         }
-        if (compressor.option("evaluate") && compressor.option("reduce_vars")) {
+        if (compressor.option("evaluate")
+            && compressor.option("reduce_vars")
+            && is_lhs(self, compressor.parent()) !== self) {
             var d = self.definition();
             var fixed = self.fixed_value();
             if (fixed) {
@@ -3603,21 +3630,45 @@ merge(Compressor.prototype, {
                     var init = fixed.evaluate(compressor);
                     if (init !== fixed) {
                         init = make_node_from_constant(init, fixed);
-                        var value = best_of_expression(init.optimize(compressor), fixed).print_to_string().length;
+                        var value = init.optimize(compressor).print_to_string().length;
+                        var fn;
+                        if (has_symbol_ref(fixed)) {
+                            fn = function() {
+                                var result = init.optimize(compressor);
+                                return result === init ? result.clone(true) : result;
+                            };
+                        } else {
+                            value = Math.min(value, fixed.print_to_string().length);
+                            fn = function() {
+                                var result = best_of_expression(init.optimize(compressor), fixed);
+                                return result === init || result === fixed ? result.clone(true) : result;
+                            };
+                        }
                         var name = d.name.length;
-                        var freq = d.references.length;
+                        var overhead = 0;
-                        var overhead = d.global || !freq ? 0 : (name + 2 + value) / freq;
+                        if (compressor.option("unused") && (!d.global || compressor.option("toplevel"))) {
-                        d.should_replace = value <= name + overhead ? init : false;
+                            overhead = (name + 2 + value) / d.references.length;
+                        }
+                        d.should_replace = value <= name + overhead ? fn : false;
                     } else {
                         d.should_replace = false;
                     }
                 }
                 if (d.should_replace) {
-                    return best_of_expression(d.should_replace.optimize(compressor), fixed).clone(true);
+                    return d.should_replace();
                 }
             }
         }
         return self;
+
+        function has_symbol_ref(value) {
+            var found;
+            value.walk(new TreeWalker(function(node) {
+                if (node instanceof AST_SymbolRef) found = true;
+                if (found) return true;
+            }));
+            return found;
+        }
     });
 
     function is_atomic(lhs, self) {

lib/output.js

@@ -190,11 +190,7 @@ function OutputStream(options) {
     var might_need_space = false;
     var might_need_semicolon = false;
     var might_add_newline = 0;
-    var last = null;
+    var last = "";
-
-    function last_char() {
-        return last.charAt(last.length - 1);
-    };
 
     var ensure_line_len = options.max_line_len ? function() {
         if (current_col > options.max_line_len) {
@@ -218,10 +214,11 @@ function OutputStream(options) {
     function print(str) {
         str = String(str);
         var ch = str.charAt(0);
+        var prev = last.charAt(last.length - 1);
         if (might_need_semicolon) {
             might_need_semicolon = false;
 
-            if ((!ch || ";}".indexOf(ch) < 0) && !/[;]$/.test(last)) {
+            if (prev == ":" && ch == "}" || (!ch || ";}".indexOf(ch) < 0) && prev != ";") {
                 if (options.semicolons || requireSemicolonChars(ch)) {
                     OUTPUT += ";";
                     current_col++;
@@ -258,7 +255,6 @@ function OutputStream(options) {
         }
 
         if (might_need_space) {
-            var prev = last_char();
             if ((is_identifier_char(prev)
                     && (is_identifier_char(ch) || ch == "\\"))
                 || (ch == "/" && ch == prev)

package.json

@@ -4,7 +4,7 @@
   "homepage": "http://lisperator.net/uglifyjs",
   "author": "Mihai Bazon <mihai.bazon@gmail.com> (http://lisperator.net/)",
   "license": "BSD-2-Clause",
-  "version": "2.8.22",
+  "version": "2.8.23",
   "engines": {
     "node": ">=0.8.0"
   },

test/benchmark.js

@@ -11,8 +11,8 @@ if (!args.length) {
 }
 args.push("--stats");
 var urls = [
-    "https://code.jquery.com/jquery-3.1.1.js",
+    "https://code.jquery.com/jquery-3.2.1.js",
-    "https://code.angularjs.org/1.6.1/angular.js",
+    "https://cdnjs.cloudflare.com/ajax/libs/angular.js/1.6.4/angular.js",
     "https://cdnjs.cloudflare.com/ajax/libs/mathjs/3.9.0/math.js",
     "https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.js",
     "https://unpkg.com/react@15.3.2/dist/react.js",

test/compress/drop-unused.js

@@ -1029,3 +1029,38 @@ delete_assign_2: {
     }
     expect_stdout: true
 }
+
+issue_1830_1: {
+    options = {
+        unused: true,
+    }
+    input: {
+        !function() {
+            L: for (var b = console.log(1); !1;) continue L;
+        }();
+    }
+    expect: {
+        !function() {
+            L: for (console.log(1); !1;) continue L;
+        }();
+    }
+    expect_stdout: "1"
+}
+
+issue_1830_2: {
+    options = {
+        unused: true,
+    }
+    input: {
+        !function() {
+            L: for (var a = 1, b = console.log(a); --a;) continue L;
+        }();
+    }
+    expect: {
+        !function() {
+            var a = 1;
+            L: for (console.log(a); --a;) continue L;
+        }();
+    }
+    expect_stdout: "1"
+}

test/compress/functions.js

@@ -93,3 +93,57 @@ issue_485_crashing_1530: {
         this, void 0;
     }
 }
+
+issue_1841_1: {
+    options = {
+        keep_fargs: false,
+        pure_getters: "strict",
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        var b = 10;
+        !function(arg) {
+            for (var key in "hi")
+                var n = arg.baz, n = [ b = 42 ];
+        }(--b);
+        console.log(b);
+    }
+    expect: {
+        var b = 10;
+        !function() {
+            for (var key in "hi") {
+                b = 42;
+            }
+        }(--b);
+        console.log(b);
+    }
+    expect_exact: "42"
+}
+
+issue_1841_2: {
+    options = {
+        keep_fargs: false,
+        pure_getters: false,
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        var b = 10;
+        !function(arg) {
+            for (var key in "hi")
+                var n = arg.baz, n = [ b = 42 ];
+        }(--b);
+        console.log(b);
+    }
+    expect: {
+        var b = 10;
+        !function(arg) {
+            for (var key in "hi") {
+                arg.baz, b = 42;
+            }
+        }(--b);
+        console.log(b);
+    }
+    expect_exact: "42"
+}

test/compress/issue-1656.js

@@ -35,11 +35,11 @@ f7: {
         console.log(a, b);
     }
     expect_exact: [
-        "var a = 100, b = 10;",
+        "var b = 10;",
         "",
         "!function() {",
-        "    for (;b = a, !1; ) ;",
+        "    for (;b = 100, !1; ) ;",
-        "}(), console.log(a, b);",
+        "}(), console.log(100, b);",
     ]
     expect_stdout: true
 }

test/compress/issue-1833.js

@@ -0,0 +1,134 @@
+iife_for: {
+    options = {
+        negate_iife: true,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        function f() {
+            function g() {
+                L: for (;;) break L;
+            }
+            g();
+        }
+        f();
+    }
+    expect: {
+        !function() {
+            !function() {
+                L: for (;;) break L;
+            }();
+        }();
+    }
+}
+
+iife_for_in: {
+    options = {
+        negate_iife: true,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        function f() {
+            function g() {
+                L: for (var a in x) break L;
+            }
+            g();
+        }
+        f();
+    }
+    expect: {
+        !function() {
+            !function() {
+                L: for (var a in x) break L;
+            }();
+        }();
+    }
+}
+
+iife_do: {
+    options = {
+        negate_iife: true,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        function f() {
+            function g() {
+                L: do {
+                    break L;
+                } while (1);
+            }
+            g();
+        }
+        f();
+    }
+    expect: {
+        !function() {
+            !function() {
+                L: do {
+                    break L;
+                } while (1);
+            }();
+        }();
+    }
+}
+
+iife_while: {
+    options = {
+        negate_iife: true,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        function f() {
+            function g() {
+                L: while (1) break L;
+            }
+            g();
+        }
+        f();
+    }
+    expect: {
+        !function() {
+            !function() {
+                L: while (1) break L;
+            }();
+        }();
+    }
+}
+
+label_do: {
+    options = {
+        evaluate: true,
+        loops: true,
+    }
+    input: {
+        L: do {
+            continue L;
+        } while (0);
+    }
+    expect: {
+        L: do {
+            continue L;
+        } while (0);
+    }
+}
+
+label_while: {
+    options = {
+        evaluate: true,
+        dead_code: true,
+        loops: true,
+    }
+    input: {
+        function f() {
+            L: while (0) continue L;
+        }
+    }
+    expect_exact: "function f(){L:;}"
+}

test/compress/reduce_vars.js

@@ -300,7 +300,7 @@ unsafe_evaluate_array: {
     }
 }
 
-unsafe_evaluate_equality: {
+unsafe_evaluate_equality_1: {
     options = {
         evaluate     : true,
         reduce_vars  : true,
@@ -308,47 +308,62 @@ unsafe_evaluate_equality: {
         unused       : true
     }
     input: {
-        function f0(){
+        function f0() {
             var a = {};
-            console.log(a === a);
+            return a === a;
         }
-
+        function f1() {
-        function f1(){
             var a = [];
-            console.log(a === a);
+            return a === a;
         }
+        console.log(f0(), f1());
+    }
+    expect: {
+        function f0() {
+            return true;
+        }
+        function f1() {
+            return true;
+        }
+        console.log(f0(), f1());
+    }
+    expect_stdout: true
+}
 
-        function f2(){
+unsafe_evaluate_equality_2: {
+    options = {
+        collapse_vars: true,
+        evaluate     : true,
+        passes       : 2,
+        reduce_vars  : true,
+        unsafe       : true,
+        unused       : true
+    }
+    input: {
+        function f2() {
             var a = {a:1, b:2};
             var b = a;
             var c = a;
-            console.log(b === c);
+            return b === c;
         }
-
+        function f3() {
-        function f3(){
             var a = [1, 2, 3];
             var b = a;
             var c = a;
-            console.log(b === c);
+            return b === c;
         }
+        console.log(f2(), f3());
     }
     expect: {
-        function f0(){
+        function f2() {
-            console.log(true);
+            return true;
         }
-
+        function f3() {
-        function f1(){
+            return true;
-            console.log(true);
-        }
-
-        function f2(){
-            console.log(true);
-        }
-
-        function f3(){
-            console.log(true);
         }
+        console.log(f2(), f3());
     }
+    expect_stdout: true
 }
 
 passes: {
@@ -1995,3 +2010,115 @@ catch_var: {
     }
     expect_stdout: "true"
 }
+
+issue_1814_1: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        const a = 42;
+        !function() {
+            var b = a;
+            !function(a) {
+                console.log(a++, b);
+            }(0);
+        }();
+    }
+    expect: {
+        const a = 42;
+        !function() {
+            !function(a) {
+                console.log(a++, 42);
+            }(0);
+        }();
+    }
+    expect_stdout: "0 42"
+}
+
+issue_1814_2: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        const a = "32";
+        !function() {
+            var b = a + 1;
+            !function(a) {
+                console.log(a++, b);
+            }(0);
+        }();
+    }
+    expect: {
+        const a = "32";
+        !function() {
+            !function(a) {
+                console.log(a++, "321");
+            }(0);
+        }();
+    }
+    expect_stdout: "0 '321'"
+}
+
+try_abort: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        !function() {
+            try {
+                var a = 1;
+                throw "";
+                var b = 2;
+            } catch (e) {
+            }
+            console.log(a, b);
+        }();
+    }
+    expect: {
+        !function() {
+            try {
+                var a = 1;
+                throw "";
+                var b = 2;
+            } catch (e) {
+            }
+            console.log(a, b);
+        }();
+    }
+    expect_stdout: "1 undefined"
+}
+
+issue_1865: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+        unsafe: true,
+    }
+    input: {
+        function f(some) {
+            some.thing = false;
+        }
+        console.log(function() {
+            var some = { thing: true };
+            f(some);
+            return some.thing;
+        }());
+    }
+    expect: {
+        function f(some) {
+            some.thing = false;
+        }
+        console.log(function() {
+            var some = { thing: true };
+            f(some);
+            return some.thing;
+        }());
+    }
+    expect_stdout: true
+}

test/sandbox.js

@@ -1,15 +1,35 @@
 var vm = require("vm");
 
+function safe_log(arg) {
+    if (arg) switch (typeof arg) {
+      case "function":
+        return arg.toString();
+      case "object":
+        if (/Error$/.test(arg.name)) return arg.toString();
+        arg.constructor.toString();
+        for (var key in arg) {
+            arg[key] = safe_log(arg[key]);
+        }
+    }
+    return arg;
+}
+
 var FUNC_TOSTRING = [
     "Function.prototype.toString = Function.prototype.valueOf = function() {",
-    "    var ids = [];",
+    "    var id = 0;",
     "    return function() {",
-    "        var i = ids.indexOf(this);",
+    '        if (this === Array) return "[Function: Array]";',
-    "        if (i < 0) {",
+    '        if (this === Object) return "[Function: Object]";',
-    "            i = ids.length;",
+    "        var i = this.name;",
-    "            ids.push(this);",
+    '        if (typeof i != "number") {',
+    "            i = ++id;",
+    '            Object.defineProperty(this, "name", {',
+    "                get: function() {",
+    "                    return i;",
+    "                }",
+    "            });",
     "        }",
-    '        return "[Function: __func_" + i + "__]";',
+    '        return "[Function: " + i + "]";',
     "    }",
     "}();",
 ].join("\n");
@@ -21,16 +41,14 @@ exports.run_code = function(code) {
     };
     try {
         vm.runInNewContext([
-            "!function() {",
             FUNC_TOSTRING,
+            "!function() {",
             code,
             "}();",
         ].join("\n"), {
             console: {
                 log: function() {
-                    return console.log.apply(console, [].map.call(arguments, function(arg) {
+                    return console.log.apply(console, [].map.call(arguments, safe_log));
-                        return typeof arg == "function" || arg && /Error$/.test(arg.name) ? arg.toString() : arg;
-                    }));
                 }
             }
         }, { timeout: 5000 });

test/ufuzz.js

@@ -2,7 +2,7 @@
 // derived from https://github.com/qfox/uglyfuzzer by Peter van der Zee
 "use strict";
 
-// check both cli and file modes of nodejs (!). See #1695 for details. and the various settings of uglify.
+// check both CLI and file modes of nodejs (!). See #1695 for details. and the various settings of uglify.
 // bin/uglifyjs s.js -c && bin/uglifyjs s.js -c passes=3 && bin/uglifyjs s.js -c passes=3 -m
 // cat s.js | node && node s.js && bin/uglifyjs s.js -c | node && bin/uglifyjs s.js -c passes=3 | node && bin/uglifyjs s.js -c passes=3 -m | node
 
@@ -20,49 +20,26 @@ var MAX_GENERATED_TOPLEVELS_PER_RUN = 1;
 var MAX_GENERATION_RECURSION_DEPTH = 12;
 var INTERVAL_COUNT = 100;
 
-var STMT_BLOCK = 0;
+var STMT_ARG_TO_ID = Object.create(null);
-var STMT_IF_ELSE = 1;
+var STMTS_TO_USE = [];
-var STMT_DO_WHILE = 2;
+function STMT_(name) {
-var STMT_WHILE = 3;
+    return STMT_ARG_TO_ID[name] = STMTS_TO_USE.push(STMTS_TO_USE.length) - 1;
-var STMT_FOR_LOOP = 4;
+}
-var STMT_SEMI = 5;
+
-var STMT_EXPR = 6;
+var STMT_BLOCK = STMT_("block");
-var STMT_SWITCH = 7;
+var STMT_IF_ELSE = STMT_("ifelse");
-var STMT_VAR = 8;
+var STMT_DO_WHILE = STMT_("dowhile");
-var STMT_RETURN_ETC = 9;
+var STMT_WHILE = STMT_("while");
-var STMT_FUNC_EXPR = 10;
+var STMT_FOR_LOOP = STMT_("forloop");
-var STMT_TRY = 11;
+var STMT_FOR_IN = STMT_("forin");
-var STMT_C = 12;
+var STMT_SEMI = STMT_("semi");
-var STMTS_TO_USE = [
+var STMT_EXPR = STMT_("expr");
-    STMT_BLOCK,
+var STMT_SWITCH = STMT_("switch");
-    STMT_IF_ELSE,
+var STMT_VAR = STMT_("var");
-    STMT_DO_WHILE,
+var STMT_RETURN_ETC = STMT_("stop");
-    STMT_WHILE,
+var STMT_FUNC_EXPR = STMT_("funcexpr");
-    STMT_FOR_LOOP,
+var STMT_TRY = STMT_("try");
-    STMT_SEMI,
+var STMT_C = STMT_("c");
-    STMT_EXPR,
-    STMT_SWITCH,
-    STMT_VAR,
-    STMT_RETURN_ETC,
-    STMT_FUNC_EXPR,
-    STMT_TRY,
-    STMT_C,
-];
-var STMT_ARG_TO_ID = {
-    block: STMT_BLOCK,
-    ifelse: STMT_IF_ELSE,
-    dowhile: STMT_DO_WHILE,
-    while: STMT_WHILE,
-    forloop: STMT_FOR_LOOP,
-    semi: STMT_SEMI,
-    expr: STMT_EXPR,
-    switch: STMT_SWITCH,
-    var: STMT_VAR,
-    stop: STMT_RETURN_ETC,
-    funcexpr: STMT_FUNC_EXPR,
-    try: STMT_TRY,
-    c: STMT_C,
-};
 
 var STMT_FIRST_LEVEL_OVERRIDE = -1;
 var STMT_SECOND_LEVEL_OVERRIDE = -1;
@@ -72,6 +49,7 @@ var num_iterations = +process.argv[2] || 1/0;
 var verbose = false; // log every generated test
 var verbose_interval = false; // log every 100 generated tests
 var verbose_error = false;
+var use_strict = false;
 for (var i = 2; i < process.argv.length; ++i) {
     switch (process.argv[i]) {
       case '-v':
@@ -101,6 +79,9 @@ for (var i = 2; i < process.argv.length; ++i) {
         STMT_SECOND_LEVEL_OVERRIDE = STMT_ARG_TO_ID[name];
         if (!(STMT_SECOND_LEVEL_OVERRIDE >= 0)) throw new Error('Unknown statement name; use -? to get a list');
         break;
+      case '--use-strict':
+        use_strict = true;
+        break;
       case '--stmt-depth-from-func':
         STMT_COUNT_FROM_GLOBAL = false;
         break;
@@ -127,6 +108,7 @@ for (var i = 2; i < process.argv.length; ++i) {
         console.log('-r <int>: maximum recursion depth for generator (higher takes longer)');
         console.log('-s1 <statement name>: force the first level statement to be this one (see list below)');
         console.log('-s2 <statement name>: force the second level statement to be this one (see list below)');
+        console.log('--use-strict: generate "use strict"');
         console.log('--stmt-depth-from-func: reset statement depth counter at each function, counts from global otherwise');
         console.log('--only-stmt <statement names>: a comma delimited white list of statements that may be generated');
         console.log('--without-stmt <statement names>: a comma delimited black list of statements never to generate');
@@ -296,15 +278,26 @@ var TYPEOF_OUTCOMES = [
 
 var loops = 0;
 var funcs = 0;
+var labels = 10000;
 
 function rng(max) {
     var r = randomBytes(2).readUInt16LE(0) / 65536;
     return Math.floor(max * r);
 }
 
+function strictMode() {
+    return use_strict && rng(4) == 0 ? '"use strict";' : '';
+}
+
 function createTopLevelCode() {
-    if (rng(2) === 0) return createStatements(3, MAX_GENERATION_RECURSION_DEPTH, CANNOT_THROW, CANNOT_BREAK, CANNOT_CONTINUE, CANNOT_RETURN, 0);
+    return [
-    return createFunctions(rng(MAX_GENERATED_TOPLEVELS_PER_RUN) + 1, MAX_GENERATION_RECURSION_DEPTH, IN_GLOBAL, ANY_TYPE, CANNOT_THROW, 0);
+        strictMode(),
+        'var a = 100, b = 10, c = 0;',
+        rng(2) == 0
+        ? createStatements(3, MAX_GENERATION_RECURSION_DEPTH, CANNOT_THROW, CANNOT_BREAK, CANNOT_CONTINUE, CANNOT_RETURN, 0)
+        : createFunctions(rng(MAX_GENERATED_TOPLEVELS_PER_RUN) + 1, MAX_GENERATION_RECURSION_DEPTH, IN_GLOBAL, ANY_TYPE, CANNOT_THROW, 0),
+        'console.log(null, a, b, c);' // preceding `null` makes for a cleaner output (empty string still shows up etc)
+    ].join('\n');
 }
 
 function createFunctions(n, recurmax, inGlobal, noDecl, canThrow, stmtDepth) {
@@ -342,10 +335,22 @@ function createFunction(recurmax, inGlobal, noDecl, canThrow, stmtDepth) {
     var s = '';
     if (rng(5) === 0) {
         // functions with functions. lower the recursion to prevent a mess.
-        s = 'function ' + name + '(' + createParams() + '){' + createFunctions(rng(5) + 1, Math.ceil(recurmax * 0.7), NOT_GLOBAL, ANY_TYPE, canThrow, stmtDepth) + '}\n';
+        s = [
+            'function ' + name + '(' + createParams() + '){',
+            strictMode(),
+            createFunctions(rng(5) + 1, Math.ceil(recurmax * 0.7), NOT_GLOBAL, ANY_TYPE, canThrow, stmtDepth),
+            '}',
+            ''
+        ].join('\n');
     } else {
         // functions with statements
-        s = 'function ' + name + '(' + createParams() + '){' + createStatements(3, recurmax, canThrow, CANNOT_THROW, CANNOT_CONTINUE, CAN_RETURN, stmtDepth) + '}\n';
+        s = [
+            'function ' + name + '(' + createParams() + '){',
+            strictMode(),
+            createStatements(3, recurmax, canThrow, CANNOT_BREAK, CANNOT_CONTINUE, CAN_RETURN, stmtDepth),
+            '}',
+            ''
+        ].join('\n');
     }
 
     VAR_NAMES.length = namesLenBefore;
@@ -367,6 +372,40 @@ function createStatements(n, recurmax, canThrow, canBreak, canContinue, cannotRe
     return s;
 }
 
+function enableLoopControl(flag, defaultValue) {
+    return Array.isArray(flag) && flag.indexOf("") < 0 ? flag.concat("") : flag || defaultValue;
+}
+
+function createLabel(canBreak, canContinue) {
+    var label;
+    if (rng(10) < 3) {
+        label = ++labels;
+        if (Array.isArray(canBreak)) {
+            canBreak = canBreak.slice();
+        } else {
+            canBreak = canBreak ? [ "" ] : [];
+        }
+        canBreak.push(label);
+        if (Array.isArray(canContinue)) {
+            canContinue = canContinue.slice();
+        } else {
+            canContinue = canContinue ? [ "" ] : [];
+        }
+        canContinue.push(label);
+    }
+    return {
+        break: canBreak,
+        continue: canContinue,
+        target: label ? "L" + label + ": " : ""
+    };
+}
+
+function getLabel(label) {
+    if (!Array.isArray(label)) return "";
+    label = label[rng(label.length)];
+    return label && " L" + label;
+}
+
 function createStatement(recurmax, canThrow, canBreak, canContinue, cannotReturn, stmtDepth) {
     ++stmtDepth;
     var loop = ++loops;
@@ -382,17 +421,36 @@ function createStatement(recurmax, canThrow, canBreak, canContinue, cannotReturn
 
     switch (target) {
       case STMT_BLOCK:
-        return '{' + createStatements(rng(5) + 1, recurmax, canThrow, canBreak, canContinue, cannotReturn, stmtDepth) + '}';
+        var label = createLabel(canBreak);
+        return label.target + '{' + createStatements(rng(5) + 1, recurmax, canThrow, label.break, canContinue, cannotReturn, stmtDepth) + '}';
       case STMT_IF_ELSE:
         return 'if (' + createExpression(recurmax, COMMA_OK, stmtDepth, canThrow) + ')' + createStatement(recurmax, canThrow, canBreak, canContinue, cannotReturn, stmtDepth) + (rng(2) === 1 ? ' else ' + createStatement(recurmax, canThrow, canBreak, canContinue, cannotReturn, stmtDepth) : '');
       case STMT_DO_WHILE:
-        return '{var brake' + loop + ' = 5; do {' + createStatement(recurmax, canThrow, CAN_BREAK, CAN_CONTINUE, cannotReturn, stmtDepth) + '} while ((' + createExpression(recurmax, COMMA_OK, stmtDepth, canThrow) + ') && --brake' + loop + ' > 0);}';
+        var label = createLabel(canBreak, canContinue);
+        canBreak = label.break || enableLoopControl(canBreak, CAN_BREAK);
+        canContinue = label.continue || enableLoopControl(canContinue, CAN_CONTINUE);
+        return '{var brake' + loop + ' = 5; ' + label.target + 'do {' + createStatement(recurmax, canThrow, canBreak, canContinue, cannotReturn, stmtDepth) + '} while ((' + createExpression(recurmax, COMMA_OK, stmtDepth, canThrow) + ') && --brake' + loop + ' > 0);}';
       case STMT_WHILE:
-        return '{var brake' + loop + ' = 5; while ((' + createExpression(recurmax, COMMA_OK, stmtDepth, canThrow) + ') && --brake' + loop + ' > 0)' + createStatement(recurmax, canThrow, CAN_BREAK, CAN_CONTINUE, cannotReturn, stmtDepth) + '}';
+        var label = createLabel(canBreak, canContinue);
+        canBreak = label.break || enableLoopControl(canBreak, CAN_BREAK);
+        canContinue = label.continue || enableLoopControl(canContinue, CAN_CONTINUE);
+        return '{var brake' + loop + ' = 5; ' + label.target + 'while ((' + createExpression(recurmax, COMMA_OK, stmtDepth, canThrow) + ') && --brake' + loop + ' > 0)' + createStatement(recurmax, canThrow, canBreak, canContinue, cannotReturn, stmtDepth) + '}';
       case STMT_FOR_LOOP:
-        return 'for (var brake' + loop + ' = 5; (' + createExpression(recurmax, COMMA_OK, stmtDepth, canThrow) + ') && brake' + loop + ' > 0; --brake' + loop + ')' + createStatement(recurmax, canThrow, CAN_BREAK, CAN_CONTINUE, cannotReturn, stmtDepth);
+        var label = createLabel(canBreak, canContinue);
+        canBreak = label.break || enableLoopControl(canBreak, CAN_BREAK);
+        canContinue = label.continue || enableLoopControl(canContinue, CAN_CONTINUE);
+        return label.target + 'for (var brake' + loop + ' = 5; (' + createExpression(recurmax, COMMA_OK, stmtDepth, canThrow) + ') && brake' + loop + ' > 0; --brake' + loop + ')' + createStatement(recurmax, canThrow, canBreak, canContinue, cannotReturn, stmtDepth);
+      case STMT_FOR_IN:
+        var label = createLabel(canBreak, canContinue);
+        canBreak = label.break || enableLoopControl(canBreak, CAN_BREAK);
+        canContinue = label.continue || enableLoopControl(canContinue, CAN_CONTINUE);
+        var optElementVar = '';
+        if (rng(5) > 1) {
+            optElementVar = 'c = 1 + c; var ' + createVarName(MANDATORY) + ' = expr' + loop + '[key' + loop + ']; ';
+        }
+        return '{var expr' + loop + ' = ' + createExpression(recurmax, COMMA_OK, stmtDepth, canThrow) + '; ' + label.target + ' for (var key' + loop + ' in expr' + loop + ') {' + optElementVar + createStatement(recurmax, canThrow, canBreak, canContinue, cannotReturn, stmtDepth) + '}}';
       case STMT_SEMI:
-        return ';';
+        return use_strict && rng(20) === 0 ? '"use strict";' : ';';
       case STMT_EXPR:
         return createExpression(recurmax, COMMA_OK, stmtDepth, canThrow) + ';';
       case STMT_SWITCH:
@@ -424,8 +482,8 @@ function createStatement(recurmax, canThrow, canBreak, canContinue, cannotReturn
           case 1:
           case 2:
           case 3:
-            if (canBreak && rng(5) === 0) return 'break;';
+            if (canBreak && rng(5) === 0) return 'break' + getLabel(canBreak) + ';';
-            if (canContinue && rng(5) === 0) return 'continue;';
+            if (canContinue && rng(5) === 0) return 'continue' + getLabel(canContinue) + ';';
             if (cannotReturn) return createExpression(recurmax, NO_COMMA, stmtDepth, canThrow) + ';';
             if (rng(3) == 0) return '/*3*/return;';
             return 'return ' + createExpression(recurmax, NO_COMMA, stmtDepth, canThrow) + ';';
@@ -470,25 +528,27 @@ function createStatement(recurmax, canThrow, canBreak, canContinue, cannotReturn
 
 function createSwitchParts(recurmax, n, canThrow, canBreak, canContinue, cannotReturn, stmtDepth) {
     var hadDefault = false;
-    var s = '';
+    var s = [''];
+    canBreak = enableLoopControl(canBreak, CAN_BREAK);
     while (n-- > 0) {
         //hadDefault = n > 0; // disables weird `default` clause positioning (use when handling destabilizes)
         if (hadDefault || rng(5) > 0) {
-            s += '' +
+            s.push(
-                'case ' + createExpression(recurmax, NO_COMMA, stmtDepth, canThrow) + ':\n' +
+                'case ' + createExpression(recurmax, NO_COMMA, stmtDepth, canThrow) + ':',
-                createStatements(rng(3) + 1, recurmax, canThrow, CAN_BREAK, canContinue, cannotReturn, stmtDepth) +
+                createStatements(rng(3) + 1, recurmax, canThrow, canBreak, canContinue, cannotReturn, stmtDepth),
-                '\n' +
+                rng(10) > 0 ? ' break;' : '/* fall-through */',
-                (rng(10) > 0 ? ' break;' : '/* fall-through */') +
+                ''
-                '\n';
+            );
         } else {
             hadDefault = true;
-            s += '' +
+            s.push(
-                'default:\n' +
+                'default:',
-                createStatements(rng(3) + 1, recurmax, canThrow, CAN_BREAK, canContinue, cannotReturn, stmtDepth) +
+                createStatements(rng(3) + 1, recurmax, canThrow, canBreak, canContinue, cannotReturn, stmtDepth),
-                '\n';
+                ''
+            );
         }
     }
-    return s;
+    return s.join('\n');
 }
 
 function createExpression(recurmax, noComma, stmtDepth, canThrow) {
@@ -530,37 +590,66 @@ function _createExpression(recurmax, noComma, stmtDepth, canThrow) {
         return createExpression(recurmax, COMMA_OK, stmtDepth, canThrow);
       case p++:
         return createExpression(recurmax, noComma, stmtDepth, canThrow) + '?' + createExpression(recurmax, NO_COMMA, stmtDepth, canThrow) + ':' + createExpression(recurmax, noComma, stmtDepth, canThrow);
+      case p++:
       case p++:
         var nameLenBefore = VAR_NAMES.length;
         var name = createVarName(MAYBE); // note: this name is only accessible from _within_ the function. and immutable at that.
-        if (name === 'c') name = 'a';
+        if (name == 'c') name = 'a';
-        var s = '';
+        var s = [];
-        switch(rng(4)) {
+        switch (rng(5)) {
           case 0:
-            s = '(function ' + name + '(){' + createStatements(rng(5) + 1, recurmax, canThrow, CANNOT_BREAK, CANNOT_CONTINUE, CAN_RETURN, stmtDepth) + '})()';
+            s.push(
+                '(function ' + name + '(){',
+                strictMode(),
+                createStatements(rng(5) + 1, recurmax, canThrow, CANNOT_BREAK, CANNOT_CONTINUE, CAN_RETURN, stmtDepth),
+                '})()'
+            );
             break;
           case 1:
-            s = '+function ' + name + '(){' + createStatements(rng(5) + 1, recurmax, canThrow, CANNOT_BREAK, CANNOT_CONTINUE, CAN_RETURN, stmtDepth) + '}()';
+            s.push(
+                '+function ' + name + '(){',
+                strictMode(),
+                createStatements(rng(5) + 1, recurmax, canThrow, CANNOT_BREAK, CANNOT_CONTINUE, CAN_RETURN, stmtDepth),
+                '}()'
+            );
             break;
           case 2:
-            s = '!function ' + name + '(){' + createStatements(rng(5) + 1, recurmax, canThrow, CANNOT_BREAK, CANNOT_CONTINUE, CAN_RETURN, stmtDepth) + '}()';
+            s.push(
+                '!function ' + name + '(){',
+                strictMode(),
+                createStatements(rng(5) + 1, recurmax, canThrow, CANNOT_BREAK, CANNOT_CONTINUE, CAN_RETURN, stmtDepth),
+                '}()'
+            );
+            break;
+          case 3:
+            s.push(
+                'void function ' + name + '(){',
+                strictMode(),
+                createStatements(rng(5) + 1, recurmax, canThrow, CANNOT_BREAK, CANNOT_CONTINUE, CAN_RETURN, stmtDepth),
+                '}()'
+            );
             break;
           default:
-            s = 'void function ' + name + '(){' + createStatements(rng(5) + 1, recurmax, canThrow, CANNOT_BREAK, CANNOT_CONTINUE, CAN_RETURN, stmtDepth) + '}()';
+            var instantiate = rng(4) ? 'new ' : '';
+            s.push(
+                instantiate + 'function ' + name + '(){',
+                strictMode()
+            );
+            if (instantiate) for (var i = rng(4); --i >= 0;) {
+                if (rng(2)) s.push('this.' + getDotKey() + createAssignment() + _createBinaryExpr(recurmax, noComma, stmtDepth, canThrow) + ';');
+                else  s.push('this[' + createExpression(recurmax, COMMA_OK, stmtDepth, canThrow) + ']' + createAssignment() + _createBinaryExpr(recurmax, noComma, stmtDepth, canThrow) + ';');
+            }
+            s.push(
+                createStatements(rng(5) + 1, recurmax, canThrow, CANNOT_BREAK, CANNOT_CONTINUE, CAN_RETURN, stmtDepth),
+                '}'
+            );
             break;
         }
         VAR_NAMES.length = nameLenBefore;
-        return s;
+        return s.join('\n');
       case p++:
       case p++:
         return createTypeofExpr(recurmax, stmtDepth, canThrow);
-      case p++:
-        return [
-            'new function() {',
-            rng(2) ? '' : createExpression(recurmax, COMMA_OK, stmtDepth, canThrow) + ';',
-            'return ' + createExpression(recurmax, COMMA_OK, stmtDepth, canThrow) + ';',
-            '}'
-        ].join('\n');
       case p++:
       case p++:
         // more like a parser test but perhaps comment nodes mess up the analysis?
@@ -682,22 +771,23 @@ function _createBinaryExpr(recurmax, noComma, stmtDepth, canThrow) {
 function _createSimpleBinaryExpr(recurmax, noComma, stmtDepth, canThrow) {
     // intentionally generate more hardcore ops
     if (--recurmax < 0) return createValue();
+    var assignee, expr;
     switch (rng(30)) {
       case 0:
         return '(c = c + 1, ' + _createSimpleBinaryExpr(recurmax, noComma, stmtDepth, canThrow) + ')';
       case 1:
         return '(' + createUnarySafePrefix() + '(' + _createSimpleBinaryExpr(recurmax, noComma, stmtDepth, canThrow) + '))';
       case 2:
-        var assignee = getVarName();
+        assignee = getVarName();
         return '(' + assignee + createAssignment() + _createBinaryExpr(recurmax, noComma, stmtDepth, canThrow) + ')';
       case 3:
-        var assignee = getVarName();
+        assignee = getVarName();
-        var expr = '(' + assignee + '[' + createExpression(recurmax, COMMA_OK, stmtDepth, canThrow)
+        expr = '(' + assignee + '[' + createExpression(recurmax, COMMA_OK, stmtDepth, canThrow)
             + ']' + createAssignment() + _createBinaryExpr(recurmax, noComma, stmtDepth, canThrow) + ')';
         return canThrow && rng(10) == 0 ? expr : '(' + assignee + ' && ' + expr + ')';
       case 4:
-        var assignee = getVarName();
+        assignee = getVarName();
-        var expr = '(' + assignee + '.' + getDotKey() + createAssignment()
+        expr = '(' + assignee + '.' + getDotKey() + createAssignment()
             + _createBinaryExpr(recurmax, noComma, stmtDepth, canThrow) + ')';
         return canThrow && rng(10) == 0 ? expr : '(' + assignee + ' && ' + expr + ')';
       default:
@@ -802,8 +892,8 @@ var default_options = {
     mangle: {
         "cache": null,
         "eval": false,
+        "ie8": false,
         "keep_fnames": false,
-        "screw_ie8": true,
         "toplevel": false,
     },
     output: infer_options(UglifyJS.OutputStream),
@@ -858,17 +948,27 @@ function log(options) {
     } else {
         console.log("// !!! uglify failed !!!");
         console.log(uglify_code.stack);
+        if (typeof original_result != "string") {
+            console.log();
+            console.log();
+            console.log("original stacktrace:");
+            console.log(original_result.stack);
+        }
     }
     console.log("minify(options):");
     options = JSON.parse(options);
     console.log(options);
     console.log();
-    if (!ok) {
+    if (!ok && typeof uglify_code == "string") {
         Object.keys(default_options).forEach(log_suspects.bind(null, options));
         console.log("!!!!!! Failed... round", round);
     }
 }
 
+var fallback_options = [ JSON.stringify({
+    compress: false,
+    mangle: false
+}) ];
 var minify_options = require("./ufuzz.json").map(function(options) {
     options.fromString = true;
     return JSON.stringify(options);
@@ -882,13 +982,9 @@ for (var round = 1; round <= num_iterations; round++) {
     loops = 0;
     funcs = 0;
 
-    original_code = [
+    original_code = createTopLevelCode();
-        "var a = 100, b = 10, c = 0;",
+    original_result = sandbox.run_code(original_code);
-        createTopLevelCode(),
+    (typeof original_result != "string" ? fallback_options : minify_options).forEach(function(options) {
-        "console.log(null, a, b, c);" // preceding `null` makes for a cleaner output (empty string still shows up etc)
-    ].join("\n");
-
-    minify_options.forEach(function(options) {
         try {
             uglify_code = UglifyJS.minify(original_code, JSON.parse(options)).code;
         } catch (e) {
@@ -897,9 +993,10 @@ for (var round = 1; round <= num_iterations; round++) {
 
         ok = typeof uglify_code == "string";
         if (ok) {
-            original_result = sandbox.run_code(original_code);
             uglify_result = sandbox.run_code(uglify_code);
             ok = sandbox.same_stdout(original_result, uglify_result);
+        } else if (typeof original_result != "string") {
+            ok = uglify_code.name == original_result.name;
         }
         if (verbose || (verbose_interval && !(round % INTERVAL_COUNT)) || !ok) log(options);
         else if (verbose_error && typeof original_result != "string") {