Add rollup-plugin-minify-html-template-literals to node_modules

R=jacktfranklin@chromium.org

Bug: 1213034
Change-Id: I5da8225f60b53870a1c67d6b5d02a464c08f4eb2
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/2917088
Commit-Queue: Tim van der Lippe <tvanderlippe@chromium.org>
Reviewed-by: Jack Franklin <jacktfranklin@chromium.org>
diff --git a/node_modules/uglify-js/lib/scope.js b/node_modules/uglify-js/lib/scope.js
new file mode 100644
index 0000000..3de59b9
--- /dev/null
+++ b/node_modules/uglify-js/lib/scope.js
@@ -0,0 +1,829 @@
+/***********************************************************************
+
+  A JavaScript tokenizer / parser / beautifier / compressor.
+  https://github.com/mishoo/UglifyJS
+
+  -------------------------------- (C) ---------------------------------
+
+                           Author: Mihai Bazon
+                         <mihai.bazon@gmail.com>
+                       http://mihai.bazon.net/blog
+
+  Distributed under the BSD license:
+
+    Copyright 2012 (c) Mihai Bazon <mihai.bazon@gmail.com>
+
+    Redistribution and use in source and binary forms, with or without
+    modification, are permitted provided that the following conditions
+    are met:
+
+        * Redistributions of source code must retain the above
+          copyright notice, this list of conditions and the following
+          disclaimer.
+
+        * Redistributions in binary form must reproduce the above
+          copyright notice, this list of conditions and the following
+          disclaimer in the documentation and/or other materials
+          provided with the distribution.
+
+    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER “AS IS” AND ANY
+    EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+    IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+    PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER BE
+    LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
+    OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+    PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+    PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+    THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
+    TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
+    THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+    SUCH DAMAGE.
+
+ ***********************************************************************/
+
+"use strict";
+
+function SymbolDef(id, scope, orig, init) {
+    this.eliminated = 0;
+    this.exported = false;
+    this.global = false;
+    this.id = id;
+    this.init = init;
+    this.mangled_name = null;
+    this.name = orig.name;
+    this.orig = [ orig ];
+    this.references = [];
+    this.replaced = 0;
+    this.scope = scope;
+    this.undeclared = false;
+}
+
+SymbolDef.prototype = {
+    forEach: function(fn) {
+        this.orig.forEach(fn);
+        this.references.forEach(fn);
+    },
+    mangle: function(options) {
+        var cache = options.cache && options.cache.props;
+        if (this.global && cache && cache.has(this.name)) {
+            this.mangled_name = cache.get(this.name);
+        } else if (!this.mangled_name && !this.unmangleable(options)) {
+            var def = this.redefined();
+            if (def) {
+                this.mangled_name = def.mangled_name || def.name;
+            } else {
+                this.mangled_name = next_mangled_name(this, options);
+            }
+            if (this.global && cache) {
+                cache.set(this.name, this.mangled_name);
+            }
+        }
+    },
+    redefined: function() {
+        var self = this;
+        var scope = self.defun;
+        if (!scope) return;
+        var name = self.name;
+        var def = scope.variables.get(name)
+            || scope instanceof AST_Toplevel && scope.globals.get(name)
+            || self.orig[0] instanceof AST_SymbolConst && find_if(function(def) {
+                return def.name == name;
+            }, scope.enclosed);
+        if (def && def !== self) return def.redefined() || def;
+    },
+    unmangleable: function(options) {
+        return this.global && !options.toplevel
+            || this.exported
+            || this.undeclared
+            || !options.eval && this.scope.pinned()
+            || options.keep_fnames
+                && (this.orig[0] instanceof AST_SymbolClass
+                    || this.orig[0] instanceof AST_SymbolDefClass
+                    || this.orig[0] instanceof AST_SymbolDefun
+                    || this.orig[0] instanceof AST_SymbolLambda);
+    },
+};
+
+var unary_side_effects = makePredicate("delete ++ --");
+
+function is_lhs(node, parent) {
+    if (parent instanceof AST_Assign) return parent.left === node && node;
+    if (parent instanceof AST_DefaultValue) return parent.name === node && node;
+    if (parent instanceof AST_Destructured) return node;
+    if (parent instanceof AST_DestructuredKeyVal) return node;
+    if (parent instanceof AST_ForEnumeration) return parent.init === node && node;
+    if (parent instanceof AST_Unary) return unary_side_effects[parent.operator] && parent.expression;
+}
+
+AST_Toplevel.DEFMETHOD("figure_out_scope", function(options) {
+    options = defaults(options, {
+        cache: null,
+        ie8: false,
+    });
+
+    // pass 1: setup scope chaining and handle definitions
+    var self = this;
+    var defun = null;
+    var exported = false;
+    var next_def_id = 0;
+    var scope = self.parent_scope = null;
+    var tw = new TreeWalker(function(node, descend) {
+        if (node instanceof AST_DefClass) {
+            var save_exported = exported;
+            exported = tw.parent() instanceof AST_ExportDeclaration;
+            node.name.walk(tw);
+            exported = save_exported;
+            walk_scope(function() {
+                if (node.extends) node.extends.walk(tw);
+                node.properties.forEach(function(prop) {
+                    prop.walk(tw);
+                });
+            });
+            return true;
+        }
+        if (node instanceof AST_Definitions) {
+            var save_exported = exported;
+            exported = tw.parent() instanceof AST_ExportDeclaration;
+            descend();
+            exported = save_exported;
+            return true;
+        }
+        if (node instanceof AST_LambdaDefinition) {
+            var save_exported = exported;
+            exported = tw.parent() instanceof AST_ExportDeclaration;
+            node.name.walk(tw);
+            exported = save_exported;
+            walk_scope(function() {
+                node.argnames.forEach(function(argname) {
+                    argname.walk(tw);
+                });
+                if (node.rest) node.rest.walk(tw);
+                walk_body(node, tw);
+            });
+            return true;
+        }
+        if (node instanceof AST_SwitchBranch) {
+            node.init_vars(scope);
+            descend();
+            return true;
+        }
+        if (node instanceof AST_Try) {
+            walk_scope(function() {
+                walk_body(node, tw);
+            });
+            if (node.bcatch) node.bcatch.walk(tw);
+            if (node.bfinally) node.bfinally.walk(tw);
+            return true;
+        }
+        if (node instanceof AST_With) {
+            var s = scope;
+            do {
+                s = s.resolve();
+                if (s.uses_with) break;
+                s.uses_with = true;
+            } while (s = s.parent_scope);
+            walk_scope(descend);
+            return true;
+        }
+        if (node instanceof AST_BlockScope) {
+            walk_scope(descend);
+            return true;
+        }
+        if (node instanceof AST_Symbol) {
+            node.scope = scope;
+        }
+        if (node instanceof AST_Label) {
+            node.thedef = node;
+            node.references = [];
+        }
+        if (node instanceof AST_SymbolCatch) {
+            scope.def_variable(node).defun = defun;
+        } else if (node instanceof AST_SymbolConst) {
+            var def = scope.def_variable(node);
+            def.defun = defun;
+            if (exported) def.exported = true;
+        } else if (node instanceof AST_SymbolDefun) {
+            var def = defun.def_function(node, tw.parent());
+            if (exported) def.exported = true;
+            entangle(defun, scope);
+        } else if (node instanceof AST_SymbolFunarg) {
+            defun.def_variable(node);
+            entangle(defun, scope);
+        } else if (node instanceof AST_SymbolLambda) {
+            var def = defun.def_function(node, node.name == "arguments" ? undefined : defun);
+            if (options.ie8) def.defun = defun.parent_scope.resolve();
+        } else if (node instanceof AST_SymbolLet) {
+            var def = scope.def_variable(node);
+            if (exported) def.exported = true;
+        } else if (node instanceof AST_SymbolVar) {
+            var def = defun.def_variable(node, node instanceof AST_SymbolImport ? undefined : null);
+            if (exported) def.exported = true;
+            entangle(defun, scope);
+        }
+
+        function walk_scope(descend) {
+            node.init_vars(scope);
+            var save_defun = defun;
+            var save_scope = scope;
+            if (node instanceof AST_Scope) defun = node;
+            scope = node;
+            descend();
+            scope = save_scope;
+            defun = save_defun;
+        }
+
+        function entangle(defun, scope) {
+            if (defun === scope) return;
+            node.mark_enclosed(options);
+            var def = scope.find_variable(node.name);
+            if (node.thedef === def) return;
+            node.thedef = def;
+            def.orig.push(node);
+            node.mark_enclosed(options);
+        }
+    });
+    self.make_def = function(orig, init) {
+        return new SymbolDef(++next_def_id, this, orig, init);
+    };
+    self.walk(tw);
+
+    // pass 2: find back references and eval
+    self.globals = new Dictionary();
+    var in_arg = [];
+    var tw = new TreeWalker(function(node) {
+        if (node instanceof AST_Catch) {
+            if (!(node.argname instanceof AST_Destructured)) return;
+            in_arg.push(node);
+            node.argname.walk(tw);
+            in_arg.pop();
+            walk_body(node, tw);
+            return true;
+        }
+        if (node instanceof AST_Lambda) {
+            in_arg.push(node);
+            node.argnames.forEach(function(argname) {
+                argname.walk(tw);
+            });
+            if (node.rest) node.rest.walk(tw);
+            in_arg.pop();
+            walk_lambda(node, tw);
+            return true;
+        }
+        if (node instanceof AST_LoopControl) {
+            if (node.label) node.label.thedef.references.push(node);
+            return true;
+        }
+        if (node instanceof AST_SymbolDeclaration) {
+            var def = node.definition();
+            def.preinit = def.references.length;
+            if (node instanceof AST_SymbolCatch) {
+                // ensure mangling works if `catch` reuses a scope variable
+                var redef = def.redefined();
+                if (redef) for (var s = node.scope; s; s = s.parent_scope) {
+                    push_uniq(s.enclosed, redef);
+                    if (s === redef.scope) break;
+                }
+            } else if (node instanceof AST_SymbolConst) {
+                // ensure compression works if `const` reuses a scope variable
+                var redef = def.redefined();
+                if (redef) redef.const_redefs = true;
+            }
+            if (node.name != "arguments") return true;
+            var parent = node instanceof AST_SymbolVar && tw.parent();
+            if (parent instanceof AST_VarDef && !parent.value) return true;
+            var sym = node.scope.resolve().find_variable("arguments");
+            if (sym && is_arguments(sym)) sym.scope.uses_arguments = 3;
+            return true;
+        }
+        if (node instanceof AST_SymbolRef) {
+            var name = node.name;
+            var sym = node.scope.find_variable(name);
+            for (var i = in_arg.length; i > 0 && sym;) {
+                i = in_arg.lastIndexOf(sym.scope, i - 1);
+                if (i < 0) break;
+                var decl = sym.orig[0];
+                if (decl instanceof AST_SymbolCatch
+                    || decl instanceof AST_SymbolFunarg
+                    || decl instanceof AST_SymbolLambda) {
+                    node.in_arg = true;
+                    break;
+                }
+                sym = sym.scope.parent_scope.find_variable(name);
+            }
+            if (!sym) {
+                sym = self.def_global(node);
+            } else if (name == "arguments" && is_arguments(sym)) {
+                var parent = tw.parent();
+                if (is_lhs(node, parent)) {
+                    sym.scope.uses_arguments = 3;
+                } else if (sym.scope.uses_arguments < 2
+                    && !(parent instanceof AST_PropAccess && parent.expression === node)) {
+                    sym.scope.uses_arguments = 2;
+                } else if (!sym.scope.uses_arguments) {
+                    sym.scope.uses_arguments = true;
+                }
+            }
+            if (name == "eval") {
+                var parent = tw.parent();
+                if (parent.TYPE == "Call" && parent.expression === node) {
+                    var s = node.scope;
+                    do {
+                        s = s.resolve();
+                        if (s.uses_eval) break;
+                        s.uses_eval = true;
+                    } while (s = s.parent_scope);
+                } else if (sym.undeclared) {
+                    self.uses_eval = true;
+                }
+            }
+            if (sym.init instanceof AST_LambdaDefinition && sym.scope !== sym.init.name.scope) {
+                var scope = node.scope;
+                do {
+                    if (scope === sym.init.name.scope) break;
+                } while (scope = scope.parent_scope);
+                if (!scope) sym.init = undefined;
+            }
+            node.thedef = sym;
+            node.reference(options);
+            return true;
+        }
+    });
+    self.walk(tw);
+
+    // pass 3: fix up any scoping issue with IE8
+    if (options.ie8) self.walk(new TreeWalker(function(node) {
+        if (node instanceof AST_SymbolCatch) {
+            var scope = node.thedef.defun;
+            if (scope.name instanceof AST_SymbolLambda && scope.name.name == node.name) {
+                scope = scope.parent_scope.resolve();
+            }
+            redefine(node, scope);
+            return true;
+        }
+        if (node instanceof AST_SymbolLambda) {
+            var def = node.thedef;
+            if (!redefine(node, node.scope.parent_scope.resolve())) {
+                delete def.defun;
+            } else if (typeof node.thedef.init !== "undefined") {
+                node.thedef.init = false;
+            } else if (def.init) {
+                node.thedef.init = def.init;
+            }
+            return true;
+        }
+    }));
+
+    function is_arguments(sym) {
+        return sym.orig[0] instanceof AST_SymbolFunarg
+            && !(sym.orig[1] instanceof AST_SymbolFunarg || sym.orig[2] instanceof AST_SymbolFunarg)
+            && !is_arrow(sym.scope);
+    }
+
+    function redefine(node, scope) {
+        var name = node.name;
+        var old_def = node.thedef;
+        if (!all(old_def.orig, function(sym) {
+            return !(sym instanceof AST_SymbolConst || sym instanceof AST_SymbolLet);
+        })) return false;
+        var new_def = scope.find_variable(name);
+        if (new_def) {
+            var redef = new_def.redefined();
+            if (redef) new_def = redef;
+        } else {
+            new_def = self.globals.get(name);
+        }
+        if (new_def) {
+            new_def.orig.push(node);
+        } else {
+            new_def = scope.def_variable(node);
+        }
+        if (new_def.undeclared) self.variables.set(name, new_def);
+        if (name == "arguments" && is_arguments(old_def) && node instanceof AST_SymbolLambda) return true;
+        old_def.defun = new_def.scope;
+        old_def.forEach(function(node) {
+            node.redef = old_def;
+            node.thedef = new_def;
+            node.reference(options);
+        });
+        return true;
+    }
+});
+
+AST_Toplevel.DEFMETHOD("def_global", function(node) {
+    var globals = this.globals, name = node.name;
+    if (globals.has(name)) {
+        return globals.get(name);
+    } else {
+        var g = this.make_def(node);
+        g.undeclared = true;
+        g.global = true;
+        globals.set(name, g);
+        return g;
+    }
+});
+
+function init_block_vars(scope, parent) {
+    scope.enclosed = [];                            // variables from this or outer scope(s) that are referenced from this or inner scopes
+    scope.parent_scope = parent;                    // the parent scope (null if this is the top level)
+    scope.functions = new Dictionary();             // map name to AST_SymbolDefun (functions defined in this scope)
+    scope.variables = new Dictionary();             // map name to AST_SymbolVar (variables defined in this scope; includes functions)
+    if (parent) scope.make_def = parent.make_def;   // top-level tracking of SymbolDef instances
+}
+
+function init_scope_vars(scope, parent) {
+    init_block_vars(scope, parent);
+    scope.uses_eval = false;                        // will be set to true if this or nested scope uses the global `eval`
+    scope.uses_with = false;                        // will be set to true if this or some nested scope uses the `with` statement
+}
+
+AST_BlockScope.DEFMETHOD("init_vars", function(parent_scope) {
+    init_block_vars(this, parent_scope);
+});
+AST_Scope.DEFMETHOD("init_vars", function(parent_scope) {
+    init_scope_vars(this, parent_scope);
+});
+AST_Arrow.DEFMETHOD("init_vars", function(parent_scope) {
+    init_scope_vars(this, parent_scope);
+    return this;
+});
+AST_AsyncArrow.DEFMETHOD("init_vars", function(parent_scope) {
+    init_scope_vars(this, parent_scope);
+});
+AST_Lambda.DEFMETHOD("init_vars", function(parent_scope) {
+    init_scope_vars(this, parent_scope);
+    this.uses_arguments = false;
+    this.def_variable(new AST_SymbolFunarg({
+        name: "arguments",
+        start: this.start,
+        end: this.end,
+    }));
+    return this;
+});
+
+AST_Symbol.DEFMETHOD("mark_enclosed", function(options) {
+    var def = this.definition();
+    for (var s = this.scope; s; s = s.parent_scope) {
+        push_uniq(s.enclosed, def);
+        if (!options) {
+            delete s._var_names;
+        } else if (options.keep_fnames) {
+            s.functions.each(function(d) {
+                push_uniq(def.scope.enclosed, d);
+            });
+        }
+        if (s === def.scope) break;
+    }
+});
+
+AST_Symbol.DEFMETHOD("reference", function(options) {
+    this.definition().references.push(this);
+    this.mark_enclosed(options);
+});
+
+AST_BlockScope.DEFMETHOD("find_variable", function(name) {
+    return this.variables.get(name)
+        || this.parent_scope && this.parent_scope.find_variable(name);
+});
+
+AST_BlockScope.DEFMETHOD("def_function", function(symbol, init) {
+    var def = this.def_variable(symbol, init);
+    if (!def.init || def.init instanceof AST_LambdaDefinition) def.init = init;
+    this.functions.set(symbol.name, def);
+    return def;
+});
+
+AST_BlockScope.DEFMETHOD("def_variable", function(symbol, init) {
+    var def = this.variables.get(symbol.name);
+    if (def) {
+        def.orig.push(symbol);
+        if (def.init instanceof AST_LambdaExpression) def.init = init;
+    } else {
+        def = this.make_def(symbol, init);
+        this.variables.set(symbol.name, def);
+        def.global = !this.parent_scope;
+    }
+    return symbol.thedef = def;
+});
+
+function names_in_use(scope, options) {
+    var names = scope.names_in_use;
+    if (!names) {
+        scope.cname = -1;
+        scope.cname_holes = [];
+        scope.names_in_use = names = Object.create(null);
+        var cache = options.cache && options.cache.props;
+        scope.enclosed.forEach(function(def) {
+            if (def.unmangleable(options)) names[def.name] = true;
+            if (def.global && cache && cache.has(def.name)) {
+                names[cache.get(def.name)] = true;
+            }
+        });
+    }
+    return names;
+}
+
+function next_mangled_name(def, options) {
+    var scope = def.scope;
+    var in_use = names_in_use(scope, options);
+    var holes = scope.cname_holes;
+    var names = Object.create(null);
+    var scopes = [ scope ];
+    def.forEach(function(sym) {
+        var scope = sym.scope;
+        do {
+            if (scopes.indexOf(scope) < 0) {
+                for (var name in names_in_use(scope, options)) {
+                    names[name] = true;
+                }
+                scopes.push(scope);
+            } else break;
+        } while (scope = scope.parent_scope);
+    });
+    var name;
+    for (var i = 0; i < holes.length; i++) {
+        name = base54(holes[i]);
+        if (names[name]) continue;
+        holes.splice(i, 1);
+        in_use[name] = true;
+        return name;
+    }
+    while (true) {
+        name = base54(++scope.cname);
+        if (in_use[name] || RESERVED_WORDS[name] || options.reserved.has[name]) continue;
+        if (!names[name]) break;
+        holes.push(scope.cname);
+    }
+    in_use[name] = true;
+    return name;
+}
+
+AST_Symbol.DEFMETHOD("unmangleable", function(options) {
+    var def = this.definition();
+    return !def || def.unmangleable(options);
+});
+
+// labels are always mangleable
+AST_Label.DEFMETHOD("unmangleable", return_false);
+
+AST_Symbol.DEFMETHOD("definition", function() {
+    return this.thedef;
+});
+
+function _default_mangler_options(options) {
+    options = defaults(options, {
+        eval        : false,
+        ie8         : false,
+        keep_fnames : false,
+        reserved    : [],
+        toplevel    : false,
+        v8          : false,
+        webkit      : false,
+    });
+    if (!Array.isArray(options.reserved)) options.reserved = [];
+    // Never mangle arguments
+    push_uniq(options.reserved, "arguments");
+    options.reserved.has = makePredicate(options.reserved);
+    return options;
+}
+
+AST_Toplevel.DEFMETHOD("mangle_names", function(options) {
+    options = _default_mangler_options(options);
+
+    // We only need to mangle declaration nodes.  Special logic wired
+    // into the code generator will display the mangled name if it's
+    // present (and for AST_SymbolRef-s it'll use the mangled name of
+    // the AST_SymbolDeclaration that it points to).
+    var lname = -1;
+
+    if (options.cache && options.cache.props) {
+        var mangled_names = names_in_use(this, options);
+        options.cache.props.each(function(mangled_name) {
+            mangled_names[mangled_name] = true;
+        });
+    }
+
+    var redefined = [];
+    var tw = new TreeWalker(function(node, descend) {
+        if (node instanceof AST_LabeledStatement) {
+            // lname is incremented when we get to the AST_Label
+            var save_nesting = lname;
+            descend();
+            if (!options.v8 || !in_label(tw)) lname = save_nesting;
+            return true;
+        }
+        if (node instanceof AST_BlockScope) {
+            if (options.webkit && node instanceof AST_IterationStatement && node.init instanceof AST_Let) {
+                node.init.definitions.forEach(function(defn) {
+                    defn.name.match_symbol(function(sym) {
+                        if (!(sym instanceof AST_SymbolLet)) return;
+                        var def = sym.definition();
+                        var scope = sym.scope.parent_scope;
+                        var redef = scope.def_variable(sym);
+                        sym.thedef = def;
+                        scope.to_mangle.push(redef);
+                        def.redefined = function() {
+                            return redef;
+                        };
+                    });
+                }, true);
+            }
+            node.to_mangle = [];
+            node.variables.each(function(def) {
+                if (!defer_redef(def)) node.to_mangle.push(def);
+            });
+            descend();
+            if (options.cache && node instanceof AST_Toplevel) {
+                node.globals.each(mangle);
+            }
+            if (node instanceof AST_Defun && tw.has_directive("use asm")) {
+                var sym = new AST_SymbolRef(node.name);
+                sym.scope = node;
+                sym.reference(options);
+            }
+            node.to_mangle.forEach(mangle);
+            return true;
+        }
+        if (node instanceof AST_Label) {
+            var name;
+            do {
+                name = base54(++lname);
+            } while (RESERVED_WORDS[name]);
+            node.mangled_name = name;
+            return true;
+        }
+    });
+    this.walk(tw);
+    redefined.forEach(mangle);
+
+    function mangle(def) {
+        if (options.reserved.has[def.name]) return;
+        def.mangle(options);
+    }
+
+    function defer_redef(def) {
+        var sym = def.orig[0];
+        var redef = def.redefined();
+        if (!redef) {
+            if (!(sym instanceof AST_SymbolConst)) return false;
+            var scope = def.scope.resolve();
+            if (def.scope === scope) return false;
+            if (def.scope.parent_scope.find_variable(sym.name)) return false;
+            redef = scope.def_variable(sym);
+            scope.to_mangle.push(redef);
+        }
+        redefined.push(def);
+        def.references.forEach(reference);
+        if (sym instanceof AST_SymbolCatch || sym instanceof AST_SymbolConst) reference(sym);
+        return true;
+
+        function reference(sym) {
+            sym.thedef = redef;
+            sym.reference(options);
+            sym.thedef = def;
+        }
+    }
+
+    function in_label(tw) {
+        var level = 0, parent;
+        while (parent = tw.parent(level++)) {
+            if (parent instanceof AST_Block) return parent instanceof AST_Toplevel && !options.toplevel;
+            if (parent instanceof AST_LabeledStatement) return true;
+        }
+    }
+});
+
+AST_Toplevel.DEFMETHOD("find_colliding_names", function(options) {
+    var cache = options.cache && options.cache.props;
+    var avoid = Object.create(RESERVED_WORDS);
+    options.reserved.forEach(to_avoid);
+    this.globals.each(add_def);
+    this.walk(new TreeWalker(function(node) {
+        if (node instanceof AST_BlockScope) node.variables.each(add_def);
+    }));
+    return avoid;
+
+    function to_avoid(name) {
+        avoid[name] = true;
+    }
+
+    function add_def(def) {
+        var name = def.name;
+        if (def.global && cache && cache.has(name)) name = cache.get(name);
+        else if (!def.unmangleable(options)) return;
+        to_avoid(name);
+    }
+});
+
+AST_Toplevel.DEFMETHOD("expand_names", function(options) {
+    base54.reset();
+    base54.sort();
+    options = _default_mangler_options(options);
+    var avoid = this.find_colliding_names(options);
+    var cname = 0;
+    this.globals.each(rename);
+    this.walk(new TreeWalker(function(node) {
+        if (node instanceof AST_BlockScope) node.variables.each(rename);
+    }));
+
+    function next_name() {
+        var name;
+        do {
+            name = base54(cname++);
+        } while (avoid[name]);
+        return name;
+    }
+
+    function rename(def) {
+        if (def.global && options.cache) return;
+        if (def.unmangleable(options)) return;
+        if (options.reserved.has[def.name]) return;
+        var redef = def.redefined();
+        var name = redef ? redef.rename || redef.name : next_name();
+        def.rename = name;
+        def.forEach(function(sym) {
+            if (sym.definition() === def) sym.name = name;
+        });
+    }
+});
+
+AST_Node.DEFMETHOD("tail_node", return_this);
+AST_Sequence.DEFMETHOD("tail_node", function() {
+    return this.expressions[this.expressions.length - 1];
+});
+
+AST_Toplevel.DEFMETHOD("compute_char_frequency", function(options) {
+    options = _default_mangler_options(options);
+    base54.reset();
+    var fn = AST_Symbol.prototype.add_source_map;
+    try {
+        AST_Symbol.prototype.add_source_map = function() {
+            if (!this.unmangleable(options)) base54.consider(this.name, -1);
+        };
+        if (options.properties) {
+            AST_Dot.prototype.add_source_map = function() {
+                base54.consider(this.property, -1);
+            };
+            AST_Sub.prototype.add_source_map = function() {
+                skip_string(this.property);
+            };
+        }
+        base54.consider(this.print_to_string(), 1);
+    } finally {
+        AST_Symbol.prototype.add_source_map = fn;
+        delete AST_Dot.prototype.add_source_map;
+        delete AST_Sub.prototype.add_source_map;
+    }
+    base54.sort();
+
+    function skip_string(node) {
+        if (node instanceof AST_String) {
+            base54.consider(node.value, -1);
+        } else if (node instanceof AST_Conditional) {
+            skip_string(node.consequent);
+            skip_string(node.alternative);
+        } else if (node instanceof AST_Sequence) {
+            skip_string(node.tail_node());
+        }
+    }
+});
+
+var base54 = (function() {
+    var freq = Object.create(null);
+    function init(chars) {
+        var array = [];
+        for (var i = 0; i < chars.length; i++) {
+            var ch = chars[i];
+            array.push(ch);
+            freq[ch] = -1e-2 * i;
+        }
+        return array;
+    }
+    var digits = init("0123456789");
+    var leading = init("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ$_");
+    var chars, frequency;
+    function reset() {
+        chars = null;
+        frequency = Object.create(freq);
+    }
+    base54.consider = function(str, delta) {
+        for (var i = str.length; --i >= 0;) {
+            frequency[str[i]] += delta;
+        }
+    };
+    function compare(a, b) {
+        return frequency[b] - frequency[a];
+    }
+    base54.sort = function() {
+        chars = leading.sort(compare).concat(digits).sort(compare);
+    };
+    base54.reset = reset;
+    reset();
+    function base54(num) {
+        var ret = leading[num % 54];
+        for (num = Math.floor(num / 54); --num >= 0; num >>= 6) {
+            ret += chars[num & 0x3F];
+        }
+        return ret;
+    }
+    return base54;
+})();