Properly scope catch identifier when --screw-ie8

Fix #344

.travis.yml

@@ -0,0 +1,7 @@
+language: node_js
+node_js:
+    - "0.4"
+    - "0.6"
+    - "0.8"
+    - "0.10"
+    - "0.11"

README.md

@@ -1,5 +1,6 @@
 UglifyJS 2
 ==========
+[![Build Status](https://travis-ci.org/mishoo/UglifyJS2.png)](https://travis-ci.org/mishoo/UglifyJS2)
 
 UglifyJS is a JavaScript parser, minifier, compressor or beautifier toolkit.
 
@@ -45,55 +46,68 @@ files.
 
 The available options are:
 
-    --source-map       Specify an output file where to generate source map.
-                                                                          [string]
-    --source-map-root  The path to the original source to be included in the
-                       source map.                                        [string]
-    --source-map-url   The path to the source map to be added in //@
-                       sourceMappingURL.  Defaults to the value passed with
-                       --source-map.                                      [string]
-    --in-source-map    Input source map, useful if you're compressing JS that was
-                       generated from some other original code.
-    --screw-ie8        Pass this flag if you don't care about full compliance with
-                       Internet Explorer 6-8 quirks (by default UglifyJS will try
-                       to be IE-proof).
-    -p, --prefix       Skip prefix for original filenames that appear in source
-                       maps. For example -p 3 will drop 3 directories from file
-                       names and ensure they are relative paths.
-    -o, --output       Output file (default STDOUT).
-    -b, --beautify     Beautify output/specify output options.            [string]
-    -m, --mangle       Mangle names/pass mangler options.                 [string]
-    -r, --reserved     Reserved names to exclude from mangling.
-    -c, --compress     Enable compressor/pass compressor options. Pass options
-                       like -c hoist_vars=false,if_return=false. Use -c with no
-                       argument to use the default compression options.   [string]
-    -d, --define       Global definitions                                 [string]
-    --comments         Preserve copyright comments in the output. By default this
-                       works like Google Closure, keeping JSDoc-style comments
-                       that contain "@license" or "@preserve". You can optionally
-                       pass one of the following arguments to this flag:
-                       - "all" to keep all comments
-                       - a valid JS regexp (needs to start with a slash) to keep
-                       only comments that match.
-                       Note that currently not *all* comments can be kept when
-                       compression is on, because of dead code removal or
-                       cascading statements into sequences.               [string]
-    --stats            Display operations run time on STDERR.            [boolean]
-    --acorn            Use Acorn for parsing.                            [boolean]
-    --spidermonkey     Assume input files are SpiderMonkey AST format (as JSON).
-                                                                         [boolean]
-    --self             Build itself (UglifyJS2) as a library (implies
-                       --wrap=UglifyJS --export-all)                     [boolean]
-    --wrap             Embed everything in a big function, making the “exports”
-                       and “global” variables available. You need to pass an
-                       argument to this option to specify the name that your
-                       module will take when included in, say, a browser.
-                                                                          [string]
-    --export-all       Only used when --wrap, this tells UglifyJS to add code to
-                       automatically export all globals.                 [boolean]
-    --lint             Display some scope warnings                       [boolean]
-    -v, --verbose      Verbose                                           [boolean]
-    -V, --version      Print version number and exit.                    [boolean]
+```
+  --source-map       Specify an output file where to generate source map.
+                                                                        [string]
+  --source-map-root  The path to the original source to be included in the
+                     source map.                                        [string]
+  --source-map-url   The path to the source map to be added in //#
+                     sourceMappingURL.  Defaults to the value passed with
+                     --source-map.                                      [string]
+  --in-source-map    Input source map, useful if you're compressing JS that was
+                     generated from some other original code.
+  --screw-ie8        Pass this flag if you don't care about full compliance
+                     with Internet Explorer 6-8 quirks (by default UglifyJS
+                     will try to be IE-proof).                         [boolean]
+  --expr             Parse a single expression, rather than a program (for
+                     parsing JSON)                                     [boolean]
+  -p, --prefix       Skip prefix for original filenames that appear in source
+                     maps. For example -p 3 will drop 3 directories from file
+                     names and ensure they are relative paths. You can also
+                     specify -p relative, which will make UglifyJS figure out
+                     itself the relative paths between original sources, the
+                     source map and the output file.                    [string]
+  -o, --output       Output file (default STDOUT).
+  -b, --beautify     Beautify output/specify output options.            [string]
+  -m, --mangle       Mangle names/pass mangler options.                 [string]
+  -r, --reserved     Reserved names to exclude from mangling.
+  -c, --compress     Enable compressor/pass compressor options. Pass options
+                     like -c hoist_vars=false,if_return=false. Use -c with no
+                     argument to use the default compression options.   [string]
+  -d, --define       Global definitions                                 [string]
+  -e, --enclose      Embed everything in a big function, with a configurable
+                     parameter/argument list.                           [string]
+  --comments         Preserve copyright comments in the output. By default this
+                     works like Google Closure, keeping JSDoc-style comments
+                     that contain "@license" or "@preserve". You can optionally
+                     pass one of the following arguments to this flag:
+                     - "all" to keep all comments
+                     - a valid JS regexp (needs to start with a slash) to keep
+                     only comments that match.
+                     Note that currently not *all* comments can be kept when
+                     compression is on, because of dead code removal or
+                     cascading statements into sequences.               [string]
+  --preamble         Preamble to prepend to the output.  You can use this to
+                     insert a comment, for example for licensing information.
+                     This will not be parsed, but the source map will adjust
+                     for its presence.
+  --stats            Display operations run time on STDERR.            [boolean]
+  --acorn            Use Acorn for parsing.                            [boolean]
+  --spidermonkey     Assume input files are SpiderMonkey AST format (as JSON).
+                                                                       [boolean]
+  --self             Build itself (UglifyJS2) as a library (implies
+                     --wrap=UglifyJS --export-all)                     [boolean]
+  --wrap             Embed everything in a big function, making the “exports”
+                     and “global” variables available. You need to pass an
+                     argument to this option to specify the name that your
+                     module will take when included in, say, a browser.
+                                                                        [string]
+  --export-all       Only used when --wrap, this tells UglifyJS to add code to
+                     automatically export all globals.                 [boolean]
+  --lint             Display some scope warnings                       [boolean]
+  -v, --verbose      Verbose                                           [boolean]
+  -V, --version      Print version number and exit.                    [boolean]
+```
 
 Specify `--output` (`-o`) to declare the output file.  Otherwise the output
 goes to STDOUT.
@@ -174,32 +188,67 @@ you can pass a comma-separated list of options.  Options are in the form
 to set `true`; it's effectively a shortcut for `foo=true`).
 
 - `sequences` -- join consecutive simple statements using the comma operator
+
 - `properties` -- rewrite property access using the dot notation, for
   example `foo["bar"] → foo.bar`
+
 - `dead_code` -- remove unreachable code
+
 - `drop_debugger` -- remove `debugger;` statements
+
 - `unsafe` (default: false) -- apply "unsafe" transformations (discussion below)
+
 - `conditionals` -- apply optimizations for `if`-s and conditional
   expressions
+
 - `comparisons` -- apply certain optimizations to binary nodes, for example:
   `!(a <= b) → a > b` (only when `unsafe`), attempts to negate binary nodes,
   e.g. `a = !b && !c && !d && !e → a=!(b||c||d||e)` etc.
+
 - `evaluate` -- attempt to evaluate constant expressions
+
 - `booleans` -- various optimizations for boolean context, for example `!!a
   ? b : c → a ? b : c`
+
 - `loops` -- optimizations for `do`, `while` and `for` loops when we can
   statically determine the condition
+
 - `unused` -- drop unreferenced functions and variables
+
 - `hoist_funs` -- hoist function declarations
+
 - `hoist_vars` (default: false) -- hoist `var` declarations (this is `false`
   by default because it seems to increase the size of the output in general)
+
 - `if_return` -- optimizations for if/return and if/continue
+
 - `join_vars` -- join consecutive `var` statements
+
 - `cascade` -- small optimization for sequences, transform `x, x` into `x`
   and `x = something(), x` into `x = something()`
+
 - `warnings` -- display warnings when dropping unreachable code or unused
   declarations etc.
 
+- `negate_iife` -- negate "Immediately-Called Function Expressions"
+  where the return value is discarded, to avoid the parens that the
+  code generator would insert.
+
+- `pure_getters` -- the default is `false`.  If you pass `true` for
+  this, UglifyJS will assume that object property access
+  (e.g. `foo.bar` or `foo["bar"]`) doesn't have any side effects.
+
+- `pure_funcs` -- default `null`.  You can pass an array of names and
+  UglifyJS will assume that those functions do not produce side
+  effects.  DANGER: will not check if the name is redefined in scope.
+  An example case here, for instance `var q = Math.floor(a/b)`.  If
+  variable `q` is not used elsewhere, UglifyJS will drop it, but will
+  still keep the `Math.floor(a/b)`, not knowing what it does.  You can
+  pass `pure_funcs: [ 'Math.floor' ]` to let it know that this
+  function won't produce any side effect, in which case the whole
+  statement would get discarded.  The current implementation adds some
+  overhead (compression will be slower).
+
 ### The `unsafe` option
 
 It enables some transformations that *might* break code logic in certain
@@ -212,7 +261,7 @@ when this flag is on:
 - `String(exp)` or `exp.toString()` → `"" + exp`
 - `new Object/RegExp/Function/Error/Array (...)` → we discard the `new`
 - `typeof foo == "undefined"` → `foo === void 0`
-- `void 0` → `"undefined"` (if there is a variable named "undefined" in
+- `void 0` → `undefined` (if there is a variable named "undefined" in
   scope; we do it because the variable name will be mangled, typically
   reduced to a single character).
 
@@ -276,9 +325,6 @@ can pass additional arguments that control the code output:
   It doesn't work very well currently, but it does make the code generated
   by UglifyJS more readable.
 - `max-line-len` (default 32000) -- maximum line length (for uglified code)
-- `ie-proof` (default `true`) -- generate “IE-proof” code (for now this
-  means add brackets around the do/while in code like this: `if (foo) do
-  something(); while (bar); else ...`.
 - `bracketize` (default `false`) -- always insert brackets in `if`, `for`,
   `do`, `while` or `with` statements, even if their body is a single
   statement.
@@ -286,6 +332,10 @@ can pass additional arguments that control the code output:
   you pass `false` then whenever possible we will use a newline instead of a
   semicolon, leading to more readable output of uglified code (size before
   gzip could be smaller; size after gzip insignificantly larger).
+- `preamble` (default `null`) -- when passed it must be a string and
+  it will be prepended to the output literally.  The source map will
+  adjust for this text.  Can be used to insert a comment containing
+  licensing information, for example.
 
 ### Keeping copyright notices or other comments
 

bin/uglifyjs

@@ -7,6 +7,7 @@ var UglifyJS = require("../tools/node");
 var sys = require("util");
 var optimist = require("optimist");
 var fs = require("fs");
+var path = require("path");
 var async = require("async");
 var acorn;
 var ARGS = optimist
@@ -20,11 +21,14 @@ mangling you need to use `-c` and `-m`.\
 ")
     .describe("source-map", "Specify an output file where to generate source map.")
     .describe("source-map-root", "The path to the original source to be included in the source map.")
-    .describe("source-map-url", "The path to the source map to be added in //@ sourceMappingURL.  Defaults to the value passed with --source-map.")
+    .describe("source-map-url", "The path to the source map to be added in //# sourceMappingURL.  Defaults to the value passed with --source-map.")
     .describe("in-source-map", "Input source map, useful if you're compressing JS that was generated from some other original code.")
     .describe("screw-ie8", "Pass this flag if you don't care about full compliance with Internet Explorer 6-8 quirks (by default UglifyJS will try to be IE-proof).")
+    .describe("expr", "Parse a single expression, rather than a program (for parsing JSON)")
     .describe("p", "Skip prefix for original filenames that appear in source maps. \
-For example -p 3 will drop 3 directories from file names and ensure they are relative paths.")
+For example -p 3 will drop 3 directories from file names and ensure they are relative paths. \
+You can also specify -p relative, which will make UglifyJS figure out itself the relative paths between original sources, \
+the source map and the output file.")
     .describe("o", "Output file (default STDOUT).")
     .describe("b", "Beautify output/specify output options.")
     .describe("m", "Mangle names/pass mangler options.")
@@ -44,6 +48,10 @@ You can optionally pass one of the following arguments to this flag:\n\
 Note that currently not *all* comments can be kept when compression is on, \
 because of dead code removal or cascading statements into sequences.")
 
+    .describe("preamble", "Preamble to prepend to the output.  You can use this to insert a \
+comment, for example for licensing information.  This will not be \
+parsed, but the source map will adjust for its presence.")
+
     .describe("stats", "Display operations run time on STDERR.")
     .describe("acorn", "Use Acorn for parsing.")
     .describe("spidermonkey", "Assume input files are SpiderMonkey AST format (as JSON).")
@@ -54,6 +62,7 @@ You need to pass an argument to this option to specify the name that your module
     .describe("lint", "Display some scope warnings")
     .describe("v", "Verbose")
     .describe("V", "Print version number and exit.")
+    .describe("noerr", "Don't throw an error for unknown options in -c, -b or -m.")
 
     .alias("p", "prefix")
     .alias("o", "output")
@@ -76,6 +85,9 @@ You need to pass an argument to this option to specify the name that your module
     .string("e")
     .string("comments")
     .string("wrap")
+    .string("p")
+
+    .boolean("expr")
     .boolean("screw-ie8")
     .boolean("export-all")
     .boolean("self")
@@ -85,6 +97,7 @@ You need to pass an argument to this option to specify the name that your module
     .boolean("spidermonkey")
     .boolean("lint")
     .boolean("V")
+    .boolean("noerr")
 
     .wrap(80)
 
@@ -93,6 +106,12 @@ You need to pass an argument to this option to specify the name that your module
 
 normalize(ARGS);
 
+if (ARGS.noerr) {
+    UglifyJS.DefaultsError.croak = function(msg, defs) {
+        sys.error("WARN: " + msg);
+    };
+}
+
 if (ARGS.version || ARGS.V) {
     var json = require("../package.json");
     sys.puts(json.name + ' ' + json.version);
@@ -122,19 +141,21 @@ if (ARGS.d) {
     if (COMPRESS) COMPRESS.global_defs = getOptions("d");
 }
 
-if (ARGS.screw_ie8) {
-    if (COMPRESS) COMPRESS.screw_ie8 = true;
-    if (MANGLE) MANGLE.screw_ie8 = true;
-}
-
 if (ARGS.r) {
     if (MANGLE) MANGLE.except = ARGS.r.replace(/^\s+|\s+$/g).split(/\s*,+\s*/);
 }
 
 var OUTPUT_OPTIONS = {
-    beautify: BEAUTIFY ? true : false
+    beautify: BEAUTIFY ? true : false,
+    preamble: ARGS.preamble || null,
 };
 
+if (ARGS.screw_ie8) {
+    if (COMPRESS) COMPRESS.screw_ie8 = true;
+    if (MANGLE) MANGLE.screw_ie8 = true;
+    OUTPUT_OPTIONS.screw_ie8 = true;
+}
+
 if (BEAUTIFY)
     UglifyJS.merge(OUTPUT_OPTIONS, BEAUTIFY);
 
@@ -196,9 +217,10 @@ if (files.filter(function(el){ return el == "-" }).length > 1) {
 var STATS = {};
 var OUTPUT_FILE = ARGS.o;
 var TOPLEVEL = null;
+var P_RELATIVE = ARGS.p && ARGS.p == "relative";
 
 var SOURCE_MAP = ARGS.source_map ? UglifyJS.SourceMap({
-    file: OUTPUT_FILE,
+    file: P_RELATIVE ? path.relative(path.dirname(ARGS.source_map), OUTPUT_FILE) : OUTPUT_FILE,
     root: ARGS.source_map_root,
     orig: ORIG_MAP,
 }) : null;
@@ -220,11 +242,18 @@ try {
 async.eachLimit(files, 1, function (file, cb) {
     read_whole_file(file, function (err, code) {
         if (err) {
-            sys.error("ERROR: can't read file: " + filename);
+            sys.error("ERROR: can't read file: " + file);
             process.exit(1);
         }
         if (ARGS.p != null) {
-            file = file.replace(/^\/+/, "").split(/\/+/).slice(ARGS.p).join("/");
+            if (P_RELATIVE) {
+                file = path.relative(path.dirname(ARGS.source_map), file);
+            } else {
+                var p = parseInt(ARGS.p, 10);
+                if (!isNaN(p)) {
+                    file = file.replace(/^\/+/, "").split(/\/+/).slice(ARGS.p).join("/");
+                }
+            }
         }
         time_it("parse", function(){
             if (ARGS.spidermonkey) {
@@ -235,16 +264,26 @@ async.eachLimit(files, 1, function (file, cb) {
             else if (ARGS.acorn) {
                 TOPLEVEL = acorn.parse(code, {
                     locations     : true,
-                    trackComments : true,
                     sourceFile    : file,
                     program       : TOPLEVEL
                 });
             }
             else {
-                TOPLEVEL = UglifyJS.parse(code, {
-                    filename: file,
-                    toplevel: TOPLEVEL
-                });
+                try {
+                    TOPLEVEL = UglifyJS.parse(code, {
+                        filename   : file,
+                        toplevel   : TOPLEVEL,
+                        expression : ARGS.expr,
+                    });
+                } catch(ex) {
+                    if (ex instanceof UglifyJS.JS_Parse_Error) {
+                        sys.error("Parse error at " + file + ":" + ex.line + "," + ex.col);
+                        sys.error(ex.message);
+                        sys.error(ex.stack);
+                        process.exit(1);
+                    }
+                    throw ex;
+                }
             };
         });
         cb();
@@ -260,11 +299,12 @@ async.eachLimit(files, 1, function (file, cb) {
 
     if (ARGS.enclose) {
         var arg_parameter_list = ARGS.enclose;
-
-        if (!(arg_parameter_list instanceof Array)) {
+        if (arg_parameter_list === true) {
+            arg_parameter_list = [];
+        }
+        else if (!(arg_parameter_list instanceof Array)) {
             arg_parameter_list = [arg_parameter_list];
         }
-
         TOPLEVEL = TOPLEVEL.wrap_enclose(arg_parameter_list);
     }
 
@@ -305,7 +345,12 @@ async.eachLimit(files, 1, function (file, cb) {
 
     if (SOURCE_MAP) {
         fs.writeFileSync(ARGS.source_map, SOURCE_MAP, "utf8");
-        output += "\n/*\n//@ sourceMappingURL=" + (ARGS.source_map_url || ARGS.source_map) + "\n*/";
+        var source_map_url = ARGS.source_map_url || (
+            P_RELATIVE
+                ? path.relative(path.dirname(OUTPUT_FILE), ARGS.source_map)
+                : ARGS.source_map
+        );
+        output += "\n//# sourceMappingURL=" + source_map_url;
     }
 
     if (OUTPUT_FILE) {
@@ -344,7 +389,7 @@ function getOptions(x, constants) {
     if (x !== true) {
         var ast;
         try {
-            ast = UglifyJS.parse(x);
+            ast = UglifyJS.parse(x, { expression: true });
         } catch(ex) {
             if (ex instanceof UglifyJS.JS_Parse_Error) {
                 sys.error("Error parsing arguments in: " + x);
@@ -352,8 +397,6 @@ function getOptions(x, constants) {
             }
         }
         ast.walk(new UglifyJS.TreeWalker(function(node){
-            if (node instanceof UglifyJS.AST_Toplevel) return; // descend
-            if (node instanceof UglifyJS.AST_SimpleStatement) return; // descend
             if (node instanceof UglifyJS.AST_Seq) return; // descend
             if (node instanceof UglifyJS.AST_Assign) {
                 var name = node.left.print_to_string({ beautify: false }).replace(/-/g, "_");
@@ -363,6 +406,11 @@ function getOptions(x, constants) {
                 ret[name] = value;
                 return true;    // no descend
             }
+            if (node instanceof UglifyJS.AST_Symbol || node instanceof UglifyJS.AST_Binary) {
+                var name = node.print_to_string({ beautify: false }).replace(/-/g, "_");
+                ret[name] = true;
+                return true;    // no descend
+            }
             sys.error(node.TYPE)
             sys.error("Error parsing arguments in: " + x);
             process.exit(1);

lib/ast.js

@@ -197,6 +197,10 @@ var AST_LabeledStatement = DEFNODE("LabeledStatement", "label", {
     }
 }, AST_StatementWithBody);
 
+var AST_IterationStatement = DEFNODE("IterationStatement", null, {
+    $documentation: "Internal class.  All loops inherit from it."
+}, AST_StatementWithBody);
+
 var AST_DWLoop = DEFNODE("DWLoop", "condition", {
     $documentation: "Base class for do/while statements",
     $propdoc: {
@@ -208,7 +212,7 @@ var AST_DWLoop = DEFNODE("DWLoop", "condition", {
             this.body._walk(visitor);
         });
     }
-}, AST_StatementWithBody);
+}, AST_IterationStatement);
 
 var AST_Do = DEFNODE("Do", null, {
     $documentation: "A `do` statement",
@@ -233,7 +237,7 @@ var AST_For = DEFNODE("For", "init condition step", {
             this.body._walk(visitor);
         });
     }
-}, AST_StatementWithBody);
+}, AST_IterationStatement);
 
 var AST_ForIn = DEFNODE("ForIn", "init name object", {
     $documentation: "A `for ... in` statement",
@@ -249,7 +253,7 @@ var AST_ForIn = DEFNODE("ForIn", "init name object", {
             this.body._walk(visitor);
         });
     }
-}, AST_StatementWithBody);
+}, AST_IterationStatement);
 
 var AST_With = DEFNODE("With", "expression", {
     $documentation: "A `with` statement",
@@ -367,7 +371,7 @@ var AST_Lambda = DEFNODE("Lambda", "name argnames uses_arguments", {
 }, AST_Scope);
 
 var AST_Accessor = DEFNODE("Accessor", null, {
-    $documentation: "A setter/getter function"
+    $documentation: "A setter/getter function.  The `name` property is always null."
 }, AST_Lambda);
 
 var AST_Function = DEFNODE("Function", null, {
@@ -494,12 +498,6 @@ var AST_Try = DEFNODE("Try", "bcatch bfinally", {
     }
 }, AST_Block);
 
-// XXX: this is wrong according to ECMA-262 (12.4).  the catch block
-// should introduce another scope, as the argname should be visible
-// only inside the catch block.  However, doing it this way because of
-// IE which simply introduces the name in the surrounding scope.  If
-// we ever want to fix this then AST_Catch should inherit from
-// AST_Scope.
 var AST_Catch = DEFNODE("Catch", "argname", {
     $documentation: "A `catch` node; only makes sense as part of a `try` statement",
     $propdoc: {
@@ -511,7 +509,7 @@ var AST_Catch = DEFNODE("Catch", "argname", {
             walk_body(this, visitor);
         });
     }
-}, AST_Block);
+}, AST_Scope);
 
 var AST_Finally = DEFNODE("Finally", null, {
     $documentation: "A `finally` node; only makes sense as part of a `try` statement"
@@ -752,7 +750,7 @@ var AST_Object = DEFNODE("Object", "properties", {
 var AST_ObjectProperty = DEFNODE("ObjectProperty", "key value", {
     $documentation: "Base class for literal object properties",
     $propdoc: {
-        key: "[string] the property name; it's always a plain string in our AST, no matter if it was a string, number or identifier in original code",
+        key: "[string] the property name converted to a string for ObjectKeyVal.  For setters and getters this is an arbitrary AST_Node.",
         value: "[AST_Node] property value.  For setters and getters this is an AST_Function."
     },
     _walk: function(visitor) {
@@ -821,7 +819,11 @@ var AST_SymbolCatch = DEFNODE("SymbolCatch", null, {
 var AST_Label = DEFNODE("Label", "references", {
     $documentation: "Symbol naming a label (declaration)",
     $propdoc: {
-        references: "[AST_LabelRef*] a list of nodes referring to this label"
+        references: "[AST_LoopControl*] a list of nodes referring to this label"
+    },
+    initialize: function() {
+        this.references = [];
+        this.thedef = this;
     }
 }, AST_Symbol);
 
@@ -945,6 +947,9 @@ TreeWalker.prototype = {
             if (x instanceof type) return x;
         }
     },
+    has_directive: function(type) {
+        return this.find_parent(AST_Scope).has_directive(type);
+    },
     in_boolean_context: function() {
         var stack = this.stack;
         var i = stack.length, self = stack[--i];
@@ -965,21 +970,15 @@ TreeWalker.prototype = {
     },
     loopcontrol_target: function(label) {
         var stack = this.stack;
-        if (label) {
-            for (var i = stack.length; --i >= 0;) {
-                var x = stack[i];
-                if (x instanceof AST_LabeledStatement && x.label.name == label.name) {
-                    return x.body;
-                }
-            }
-        } else {
-            for (var i = stack.length; --i >= 0;) {
-                var x = stack[i];
-                if (x instanceof AST_Switch
-                    || x instanceof AST_For
-                    || x instanceof AST_ForIn
-                    || x instanceof AST_DWLoop) return x;
+        if (label) for (var i = stack.length; --i >= 0;) {
+            var x = stack[i];
+            if (x instanceof AST_LabeledStatement && x.label.name == label.name) {
+                return x.body;
             }
+        } else for (var i = stack.length; --i >= 0;) {
+            var x = stack[i];
+            if (x instanceof AST_Switch || x instanceof AST_IterationStatement)
+                return x;
         }
     }
 };

lib/compress.js

@@ -66,6 +66,9 @@ function Compressor(options, false_by_default) {
         join_vars     : !false_by_default,
         cascade       : !false_by_default,
         side_effects  : !false_by_default,
+        pure_getters  : false,
+        pure_funcs    : null,
+        negate_iife   : !false_by_default,
         screw_ie8     : false,
 
         warnings      : true,
@@ -82,22 +85,16 @@ merge(Compressor.prototype, {
     },
     before: function(node, descend, in_list) {
         if (node._squeezed) return node;
+        var was_scope = false;
         if (node instanceof AST_Scope) {
-            node.drop_unused(this);
             node = node.hoist_declarations(this);
+            was_scope = true;
         }
         descend(node, this);
         node = node.optimize(this);
-        if (node instanceof AST_Scope) {
-            // dead code removal might leave further unused declarations.
-            // this'll usually save very few bytes, but the performance
-            // hit seems negligible so I'll just drop it here.
-
-            // no point to repeat warnings.
-            var save_warnings = this.options.warnings;
-            this.options.warnings = false;
+        if (was_scope && node instanceof AST_Scope) {
             node.drop_unused(this);
-            this.options.warnings = save_warnings;
+            descend(node, this);
         }
         node._squeezed = true;
         return node;
@@ -214,6 +211,11 @@ merge(Compressor.prototype, {
                 statements = join_consecutive_vars(statements, compressor);
             }
         } while (CHANGED);
+
+        if (compressor.option("negate_iife")) {
+            negate_iifes(statements, compressor);
+        }
+
         return statements;
 
         function eliminate_spurious_blocks(statements) {
@@ -318,7 +320,7 @@ merge(Compressor.prototype, {
                                || (ab instanceof AST_Continue && self === loop_body(lct))
                                || (ab instanceof AST_Break && lct instanceof AST_BlockStatement && self === lct))) {
                         if (ab.label) {
-                            remove(ab.label.thedef.references, ab.label);
+                            remove(ab.label.thedef.references, ab);
                         }
                         CHANGED = true;
                         var body = as_statement_array(stat.body).slice(0, -1);
@@ -340,7 +342,7 @@ merge(Compressor.prototype, {
                                || (ab instanceof AST_Continue && self === loop_body(lct))
                                || (ab instanceof AST_Break && lct instanceof AST_BlockStatement && self === lct))) {
                         if (ab.label) {
-                            remove(ab.label.thedef.references, ab.label);
+                            remove(ab.label.thedef.references, ab);
                         }
                         CHANGED = true;
                         stat = stat.clone();
@@ -379,7 +381,7 @@ merge(Compressor.prototype, {
                              && loop_body(lct) === self) || (stat instanceof AST_Continue
                                                              && loop_body(lct) === self)) {
                             if (stat.label) {
-                                remove(stat.label.thedef.references, stat.label);
+                                remove(stat.label.thedef.references, stat);
                             }
                         } else {
                             a.push(stat);
@@ -497,6 +499,40 @@ merge(Compressor.prototype, {
             }, []);
         };
 
+        function negate_iifes(statements, compressor) {
+            statements.forEach(function(stat){
+                if (stat instanceof AST_SimpleStatement) {
+                    stat.body = (function transform(thing) {
+                        return thing.transform(new TreeTransformer(function(node){
+                            if (node instanceof AST_Call && node.expression instanceof AST_Function) {
+                                return make_node(AST_UnaryPrefix, node, {
+                                    operator: "!",
+                                    expression: node
+                                });
+                            }
+                            else if (node instanceof AST_Call) {
+                                node.expression = transform(node.expression);
+                            }
+                            else if (node instanceof AST_Seq) {
+                                node.car = transform(node.car);
+                            }
+                            else if (node instanceof AST_Conditional) {
+                                var expr = transform(node.condition);
+                                if (expr !== node.condition) {
+                                    // it has been negated, reverse
+                                    node.condition = expr;
+                                    var tmp = node.consequent;
+                                    node.consequent = node.alternative;
+                                    node.alternative = tmp;
+                                }
+                            }
+                            return node;
+                        }));
+                    })(stat.body);
+                }
+            });
+        };
+
     };
 
     function extract_declarations_from_unreachable_code(compressor, stat, target) {
@@ -590,14 +626,14 @@ merge(Compressor.prototype, {
         // elements.  If the node has been successfully reduced to a
         // constant, then the second element tells us the value;
         // otherwise the second element is missing.  The first element
-        // of the array is always an AST_Node descendant; when
+        // of the array is always an AST_Node descendant; if
         // evaluation was successful it's a node that represents the
-        // constant; otherwise it's the original node.
+        // constant; otherwise it's the original or a replacement node.
         AST_Node.DEFMETHOD("evaluate", function(compressor){
             if (!compressor.option("evaluate")) return [ this ];
             try {
-                var val = this._eval(), ast = make_node_from_constant(compressor, val, this);
-                return [ best_of(ast, this), val ];
+                var val = this._eval(compressor);
+                return [ best_of(make_node_from_constant(compressor, val, this), this), val ];
             } catch(ex) {
                 if (ex !== def) throw ex;
                 return [ this ];
@@ -611,10 +647,12 @@ merge(Compressor.prototype, {
             // inherits from AST_Statement; however, an AST_Function
             // isn't really a statement.  This could byte in other
             // places too. :-( Wish JS had multiple inheritance.
-            return [ this ];
+            throw def;
         });
-        function ev(node) {
-            return node._eval();
+        function ev(node, compressor) {
+            if (!compressor) throw new Error("Compressor must be passed");
+
+            return node._eval(compressor);
         };
         def(AST_Node, function(){
             throw def;          // not constant
@@ -622,69 +660,69 @@ merge(Compressor.prototype, {
         def(AST_Constant, function(){
             return this.getValue();
         });
-        def(AST_UnaryPrefix, function(){
+        def(AST_UnaryPrefix, function(compressor){
             var e = this.expression;
             switch (this.operator) {
-              case "!": return !ev(e);
+              case "!": return !ev(e, compressor);
               case "typeof":
                 // Function would be evaluated to an array and so typeof would
                 // incorrectly return 'object'. Hence making is a special case.
                 if (e instanceof AST_Function) return typeof function(){};
 
-                e = ev(e);
+                e = ev(e, compressor);
 
                 // typeof <RegExp> returns "object" or "function" on different platforms
                 // so cannot evaluate reliably
                 if (e instanceof RegExp) throw def;
 
                 return typeof e;
-              case "void": return void ev(e);
-              case "~": return ~ev(e);
+              case "void": return void ev(e, compressor);
+              case "~": return ~ev(e, compressor);
               case "-":
-                e = ev(e);
+                e = ev(e, compressor);
                 if (e === 0) throw def;
                 return -e;
-              case "+": return +ev(e);
+              case "+": return +ev(e, compressor);
             }
             throw def;
         });
-        def(AST_Binary, function(){
+        def(AST_Binary, function(c){
             var left = this.left, right = this.right;
             switch (this.operator) {
-              case "&&"         : return ev(left) &&         ev(right);
-              case "||"         : return ev(left) ||         ev(right);
-              case "|"          : return ev(left) |          ev(right);
-              case "&"          : return ev(left) &          ev(right);
-              case "^"          : return ev(left) ^          ev(right);
-              case "+"          : return ev(left) +          ev(right);
-              case "*"          : return ev(left) *          ev(right);
-              case "/"          : return ev(left) /          ev(right);
-              case "%"          : return ev(left) %          ev(right);
-              case "-"          : return ev(left) -          ev(right);
-              case "<<"         : return ev(left) <<         ev(right);
-              case ">>"         : return ev(left) >>         ev(right);
-              case ">>>"        : return ev(left) >>>        ev(right);
-              case "=="         : return ev(left) ==         ev(right);
-              case "==="        : return ev(left) ===        ev(right);
-              case "!="         : return ev(left) !=         ev(right);
-              case "!=="        : return ev(left) !==        ev(right);
-              case "<"          : return ev(left) <          ev(right);
-              case "<="         : return ev(left) <=         ev(right);
-              case ">"          : return ev(left) >          ev(right);
-              case ">="         : return ev(left) >=         ev(right);
-              case "in"         : return ev(left) in         ev(right);
-              case "instanceof" : return ev(left) instanceof ev(right);
+              case "&&"         : return ev(left, c) &&         ev(right, c);
+              case "||"         : return ev(left, c) ||         ev(right, c);
+              case "|"          : return ev(left, c) |          ev(right, c);
+              case "&"          : return ev(left, c) &          ev(right, c);
+              case "^"          : return ev(left, c) ^          ev(right, c);
+              case "+"          : return ev(left, c) +          ev(right, c);
+              case "*"          : return ev(left, c) *          ev(right, c);
+              case "/"          : return ev(left, c) /          ev(right, c);
+              case "%"          : return ev(left, c) %          ev(right, c);
+              case "-"          : return ev(left, c) -          ev(right, c);
+              case "<<"         : return ev(left, c) <<         ev(right, c);
+              case ">>"         : return ev(left, c) >>         ev(right, c);
+              case ">>>"        : return ev(left, c) >>>        ev(right, c);
+              case "=="         : return ev(left, c) ==         ev(right, c);
+              case "==="        : return ev(left, c) ===        ev(right, c);
+              case "!="         : return ev(left, c) !=         ev(right, c);
+              case "!=="        : return ev(left, c) !==        ev(right, c);
+              case "<"          : return ev(left, c) <          ev(right, c);
+              case "<="         : return ev(left, c) <=         ev(right, c);
+              case ">"          : return ev(left, c) >          ev(right, c);
+              case ">="         : return ev(left, c) >=         ev(right, c);
+              case "in"         : return ev(left, c) in         ev(right, c);
+              case "instanceof" : return ev(left, c) instanceof ev(right, c);
             }
             throw def;
         });
-        def(AST_Conditional, function(){
-            return ev(this.condition)
-                ? ev(this.consequent)
-                : ev(this.alternative);
+        def(AST_Conditional, function(compressor){
+            return ev(this.condition, compressor)
+                ? ev(this.consequent, compressor)
+                : ev(this.alternative, compressor);
         });
-        def(AST_SymbolRef, function(){
+        def(AST_SymbolRef, function(compressor){
             var d = this.definition();
-            if (d && d.constant && d.init) return ev(d.init);
+            if (d && d.constant && d.init) return ev(d.init, compressor);
             throw def;
         });
     })(function(node, func){
@@ -760,70 +798,78 @@ merge(Compressor.prototype, {
 
     // determine if expression has side effects
     (function(def){
-        def(AST_Node, function(){ return true });
+        def(AST_Node, function(compressor){ return true });
 
-        def(AST_EmptyStatement, function(){ return false });
-        def(AST_Constant, function(){ return false });
-        def(AST_This, function(){ return false });
+        def(AST_EmptyStatement, function(compressor){ return false });
+        def(AST_Constant, function(compressor){ return false });
+        def(AST_This, function(compressor){ return false });
 
-        def(AST_Block, function(){
+        def(AST_Call, function(compressor){
+            var pure = compressor.option("pure_funcs");
+            if (!pure) return true;
+            return pure.indexOf(this.expression.print_to_string()) < 0;
+        });
+
+        def(AST_Block, function(compressor){
             for (var i = this.body.length; --i >= 0;) {
-                if (this.body[i].has_side_effects())
+                if (this.body[i].has_side_effects(compressor))
                     return true;
             }
             return false;
         });
 
-        def(AST_SimpleStatement, function(){
-            return this.body.has_side_effects();
+        def(AST_SimpleStatement, function(compressor){
+            return this.body.has_side_effects(compressor);
         });
-        def(AST_Defun, function(){ return true });
-        def(AST_Function, function(){ return false });
-        def(AST_Binary, function(){
-            return this.left.has_side_effects()
-                || this.right.has_side_effects();
+        def(AST_Defun, function(compressor){ return true });
+        def(AST_Function, function(compressor){ return false });
+        def(AST_Binary, function(compressor){
+            return this.left.has_side_effects(compressor)
+                || this.right.has_side_effects(compressor);
         });
-        def(AST_Assign, function(){ return true });
-        def(AST_Conditional, function(){
-            return this.condition.has_side_effects()
-                || this.consequent.has_side_effects()
-                || this.alternative.has_side_effects();
+        def(AST_Assign, function(compressor){ return true });
+        def(AST_Conditional, function(compressor){
+            return this.condition.has_side_effects(compressor)
+                || this.consequent.has_side_effects(compressor)
+                || this.alternative.has_side_effects(compressor);
         });
-        def(AST_Unary, function(){
+        def(AST_Unary, function(compressor){
             return this.operator == "delete"
                 || this.operator == "++"
                 || this.operator == "--"
-                || this.expression.has_side_effects();
+                || this.expression.has_side_effects(compressor);
         });
-        def(AST_SymbolRef, function(){ return false });
-        def(AST_Object, function(){
+        def(AST_SymbolRef, function(compressor){ return false });
+        def(AST_Object, function(compressor){
             for (var i = this.properties.length; --i >= 0;)
-                if (this.properties[i].has_side_effects())
+                if (this.properties[i].has_side_effects(compressor))
                     return true;
             return false;
         });
-        def(AST_ObjectProperty, function(){
-            return this.value.has_side_effects();
+        def(AST_ObjectProperty, function(compressor){
+            return this.value.has_side_effects(compressor);
         });
-        def(AST_Array, function(){
+        def(AST_Array, function(compressor){
             for (var i = this.elements.length; --i >= 0;)
-                if (this.elements[i].has_side_effects())
+                if (this.elements[i].has_side_effects(compressor))
                     return true;
             return false;
         });
-        // def(AST_Dot, function(){
-        //     return this.expression.has_side_effects();
-        // });
-        // def(AST_Sub, function(){
-        //     return this.expression.has_side_effects()
-        //         || this.property.has_side_effects();
-        // });
-        def(AST_PropAccess, function(){
-            return true;
+        def(AST_Dot, function(compressor){
+            if (!compressor.option("pure_getters")) return true;
+            return this.expression.has_side_effects(compressor);
         });
-        def(AST_Seq, function(){
-            return this.car.has_side_effects()
-                || this.cdr.has_side_effects();
+        def(AST_Sub, function(compressor){
+            if (!compressor.option("pure_getters")) return true;
+            return this.expression.has_side_effects(compressor)
+                || this.property.has_side_effects(compressor);
+        });
+        def(AST_PropAccess, function(compressor){
+            return !compressor.option("pure_getters");
+        });
+        def(AST_Seq, function(compressor){
+            return this.car.has_side_effects(compressor)
+                || this.cdr.has_side_effects(compressor);
         });
     })(function(node, func){
         node.DEFMETHOD("has_side_effects", func);
@@ -907,7 +953,7 @@ merge(Compressor.prototype, {
                         node.definitions.forEach(function(def){
                             if (def.value) {
                                 initializations.add(def.name.name, def.value);
-                                if (def.value.has_side_effects()) {
+                                if (def.value.has_side_effects(compressor)) {
                                     def.value.walk(tw);
                                 }
                             }
@@ -948,7 +994,7 @@ merge(Compressor.prototype, {
             // pass 3: we should drop declarations not in_use
             var tt = new TreeTransformer(
                 function before(node, descend, in_list) {
-                    if (node instanceof AST_Lambda) {
+                    if (node instanceof AST_Lambda && !(node instanceof AST_Accessor)) {
                         for (var a = node.argnames, i = a.length; --i >= 0;) {
                             var sym = a[i];
                             if (sym.unreferenced()) {
@@ -984,7 +1030,7 @@ merge(Compressor.prototype, {
                                 line : def.name.start.line,
                                 col  : def.name.start.col
                             };
-                            if (def.value && def.value.has_side_effects()) {
+                            if (def.value && def.value.has_side_effects(compressor)) {
                                 def._unused_side_effects = true;
                                 compressor.warn("Side effects in initialization of unused variable {name} [{file}:{line},{col}]", w);
                                 return true;
@@ -1038,18 +1084,23 @@ merge(Compressor.prototype, {
                         }
                         return node;
                     }
-                    if (node instanceof AST_For && node.init instanceof AST_BlockStatement) {
+                    if (node instanceof AST_For) {
                         descend(node, this);
-                        // certain combination of unused name + side effect leads to:
-                        //    https://github.com/mishoo/UglifyJS2/issues/44
-                        // that's an invalid AST.
-                        // We fix it at this stage by moving the `var` outside the `for`.
-                        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
-                        });
+
+                        if (node.init instanceof AST_BlockStatement) {
+                            // certain combination of unused name + side effect leads to:
+                            //    https://github.com/mishoo/UglifyJS2/issues/44
+                            // that's an invalid AST.
+                            // We fix it at this stage by moving the `var` outside the `for`.
+
+                            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
+                            });
+                        }
                     }
                     if (node instanceof AST_Scope && node !== self)
                         return node;
@@ -1186,7 +1237,7 @@ merge(Compressor.prototype, {
 
     OPT(AST_SimpleStatement, function(self, compressor){
         if (compressor.option("side_effects")) {
-            if (!self.body.has_side_effects()) {
+            if (!self.body.has_side_effects(compressor)) {
                 compressor.warn("Dropping side-effect-free statement [{file}:{line},{col}]", self.start);
                 return make_node(AST_EmptyStatement, self);
             }
@@ -1570,7 +1621,7 @@ merge(Compressor.prototype, {
                     if (self.args.length != 1) {
                         return make_node(AST_Array, self, {
                             elements: self.args
-                        });
+                        }).transform(compressor);
                     }
                     break;
                   case "Object":
@@ -1584,11 +1635,80 @@ merge(Compressor.prototype, {
                     if (self.args.length == 0) return make_node(AST_String, self, {
                         value: ""
                     });
-                    return make_node(AST_Binary, self, {
+                    if (self.args.length <= 1) return make_node(AST_Binary, self, {
                         left: self.args[0],
                         operator: "+",
                         right: make_node(AST_String, self, { value: "" })
+                    }).transform(compressor);
+                    break;
+                  case "Number":
+                    if (self.args.length == 0) return make_node(AST_Number, self, {
+                        value: 0
                     });
+                    if (self.args.length == 1) return make_node(AST_UnaryPrefix, self, {
+                        expression: self.args[0],
+                        operator: "+"
+                    }).transform(compressor);
+                  case "Boolean":
+                    if (self.args.length == 0) return make_node(AST_False, self);
+                    if (self.args.length == 1) return make_node(AST_UnaryPrefix, self, {
+                        expression: make_node(AST_UnaryPrefix, null, {
+                            expression: self.args[0],
+                            operator: "!"
+                        }),
+                        operator: "!"
+                    }).transform(compressor);
+                    break;
+                  case "Function":
+                    if (all(self.args, function(x){ return x instanceof AST_String })) {
+                        // quite a corner-case, but we can handle it:
+                        //   https://github.com/mishoo/UglifyJS2/issues/203
+                        // if the code argument is a constant, then we can minify it.
+                        try {
+                            var code = "(function(" + self.args.slice(0, -1).map(function(arg){
+                                return arg.value;
+                            }).join(",") + "){" + self.args[self.args.length - 1].value + "})()";
+                            var ast = parse(code);
+                            ast.figure_out_scope({ screw_ie8: compressor.option("screw_ie8") });
+                            var comp = new Compressor(compressor.options);
+                            ast = ast.transform(comp);
+                            ast.figure_out_scope({ screw_ie8: compressor.option("screw_ie8") });
+                            ast.mangle_names();
+                            var fun;
+                            try {
+                                ast.walk(new TreeWalker(function(node){
+                                    if (node instanceof AST_Lambda) {
+                                        fun = node;
+                                        throw ast;
+                                    }
+                                }));
+                            } catch(ex) {
+                                if (ex !== ast) throw ex;
+                            };
+                            var args = fun.argnames.map(function(arg, i){
+                                return make_node(AST_String, self.args[i], {
+                                    value: arg.print_to_string()
+                                });
+                            });
+                            var code = OutputStream();
+                            AST_BlockStatement.prototype._codegen.call(fun, fun, code);
+                            code = code.toString().replace(/^\{|\}$/g, "");
+                            args.push(make_node(AST_String, self.args[self.args.length - 1], {
+                                value: code
+                            }));
+                            self.args = args;
+                            return self;
+                        } catch(ex) {
+                            if (ex instanceof JS_Parse_Error) {
+                                compressor.warn("Error parsing code passed to new Function [{file}:{line},{col}]", self.args[self.args.length - 1].start);
+                                compressor.warn(ex.toString());
+                            } else {
+                                console.log(ex);
+                                throw ex;
+                            }
+                        }
+                    }
+                    break;
                 }
             }
             else if (exp instanceof AST_Dot && exp.property == "toString" && self.args.length == 0) {
@@ -1598,15 +1718,62 @@ merge(Compressor.prototype, {
                     right: exp.expression
                 }).transform(compressor);
             }
+            else if (exp instanceof AST_Dot && exp.expression instanceof AST_Array && exp.property == "join") EXIT: {
+                var separator = self.args.length == 0 ? "," : self.args[0].evaluate(compressor)[1];
+                if (separator == null) break EXIT; // not a constant
+                var elements = exp.expression.elements.reduce(function(a, el){
+                    el = el.evaluate(compressor);
+                    if (a.length == 0 || el.length == 1) {
+                        a.push(el);
+                    } else {
+                        var last = a[a.length - 1];
+                        if (last.length == 2) {
+                            // it's a constant
+                            var val = "" + last[1] + separator + el[1];
+                            a[a.length - 1] = [ make_node_from_constant(compressor, val, last[0]), val ];
+                        } else {
+                            a.push(el);
+                        }
+                    }
+                    return a;
+                }, []);
+                if (elements.length == 0) return make_node(AST_String, self, { value: "" });
+                if (elements.length == 1) return elements[0][0];
+                if (separator == "") {
+                    var first;
+                    if (elements[0][0] instanceof AST_String
+                        || elements[1][0] instanceof AST_String) {
+                        first = elements.shift()[0];
+                    } else {
+                        first = make_node(AST_String, self, { value: "" });
+                    }
+                    return elements.reduce(function(prev, el){
+                        return make_node(AST_Binary, el[0], {
+                            operator : "+",
+                            left     : prev,
+                            right    : el[0],
+                        });
+                    }, first).transform(compressor);
+                }
+                // need this awkward cloning to not affect original element
+                // best_of will decide which one to get through.
+                var node = self.clone();
+                node.expression = node.expression.clone();
+                node.expression.expression = node.expression.expression.clone();
+                node.expression.expression.elements = elements.map(function(el){
+                    return el[0];
+                });
+                return best_of(self, node);
+            }
         }
         if (compressor.option("side_effects")) {
             if (self.expression instanceof AST_Function
                 && self.args.length == 0
-                && !AST_Block.prototype.has_side_effects.call(self.expression)) {
+                && !AST_Block.prototype.has_side_effects.call(self.expression, compressor)) {
                 return make_node(AST_Undefined, self).transform(compressor);
             }
         }
-        return self;
+        return self.evaluate(compressor)[0];
     });
 
     OPT(AST_New, function(self, compressor){
@@ -1629,7 +1796,7 @@ merge(Compressor.prototype, {
     OPT(AST_Seq, function(self, compressor){
         if (!compressor.option("side_effects"))
             return self;
-        if (!self.car.has_side_effects()) {
+        if (!self.car.has_side_effects(compressor)) {
             // we shouldn't compress (1,eval)(something) to
             // eval(something) because that changes the meaning of
             // eval (becomes lexical instead of global).
@@ -1644,12 +1811,12 @@ merge(Compressor.prototype, {
         }
         if (compressor.option("cascade")) {
             if (self.car instanceof AST_Assign
-                && !self.car.left.has_side_effects()
+                && !self.car.left.has_side_effects(compressor)
                 && self.car.left.equivalent_to(self.cdr)) {
                 return self.car;
             }
-            if (!self.car.has_side_effects()
-                && !self.cdr.has_side_effects()
+            if (!self.car.has_side_effects(compressor)
+                && !self.cdr.has_side_effects(compressor)
                 && self.car.equivalent_to(self.cdr)) {
                 return self.car;
             }
@@ -1699,6 +1866,14 @@ merge(Compressor.prototype, {
         return self.evaluate(compressor)[0];
     });
 
+    function has_side_effects_or_prop_access(node, compressor) {
+        var save_pure_getters = compressor.option("pure_getters");
+        compressor.options.pure_getters = false;
+        var ret = node.has_side_effects(compressor);
+        compressor.options.pure_getters = save_pure_getters;
+        return ret;
+    }
+
     AST_Binary.DEFMETHOD("lift_sequences", function(compressor){
         if (compressor.option("sequences")) {
             if (this.left instanceof AST_Seq) {
@@ -1710,8 +1885,8 @@ merge(Compressor.prototype, {
                 return seq;
             }
             if (this.right instanceof AST_Seq
-                && !(this.operator == "||" || this.operator == "&&")
-                && !this.left.has_side_effects()) {
+                && this instanceof AST_Assign
+                && !has_side_effects_or_prop_access(this.left, compressor)) {
                 var seq = this.right;
                 var x = seq.to_array();
                 this.right = x.pop();
@@ -1726,21 +1901,52 @@ merge(Compressor.prototype, {
     var commutativeOperators = makePredicate("== === != !== * & | ^");
 
     OPT(AST_Binary, function(self, compressor){
-        function reverse(op, force) {
-            if (force || !(self.left.has_side_effects() || self.right.has_side_effects())) {
-                if (op) self.operator = op;
-                var tmp = self.left;
-                self.left = self.right;
-                self.right = tmp;
-            }
-        };
+        var reverse = compressor.has_directive("use asm") ? noop
+            : function(op, force) {
+                if (force || !(self.left.has_side_effects(compressor) || self.right.has_side_effects(compressor))) {
+                    if (op) self.operator = op;
+                    var tmp = self.left;
+                    self.left = self.right;
+                    self.right = tmp;
+                }
+            };
         if (commutativeOperators(self.operator)) {
             if (self.right instanceof AST_Constant
                 && !(self.left instanceof AST_Constant)) {
                 // if right is a constant, whatever side effects the
                 // left side might have could not influence the
                 // result.  hence, force switch.
-                reverse(null, true);
+
+                if (!(self.left instanceof AST_Binary
+                      && PRECEDENCE[self.left.operator] >= PRECEDENCE[self.operator])) {
+                    reverse(null, true);
+                }
+            }
+            if (/^[!=]==?$/.test(self.operator)) {
+                if (self.left instanceof AST_SymbolRef && self.right instanceof AST_Conditional) {
+                    if (self.right.consequent instanceof AST_SymbolRef
+                        && self.right.consequent.definition() === self.left.definition()) {
+                        if (/^==/.test(self.operator)) return self.right.condition;
+                        if (/^!=/.test(self.operator)) return self.right.condition.negate(compressor);
+                    }
+                    if (self.right.alternative instanceof AST_SymbolRef
+                        && self.right.alternative.definition() === self.left.definition()) {
+                        if (/^==/.test(self.operator)) return self.right.condition.negate(compressor);
+                        if (/^!=/.test(self.operator)) return self.right.condition;
+                    }
+                }
+                if (self.right instanceof AST_SymbolRef && self.left instanceof AST_Conditional) {
+                    if (self.left.consequent instanceof AST_SymbolRef
+                        && self.left.consequent.definition() === self.right.definition()) {
+                        if (/^==/.test(self.operator)) return self.left.condition;
+                        if (/^!=/.test(self.operator)) return self.left.condition.negate(compressor);
+                    }
+                    if (self.left.alternative instanceof AST_SymbolRef
+                        && self.left.alternative.definition() === self.right.definition()) {
+                        if (/^==/.test(self.operator)) return self.left.condition.negate(compressor);
+                        if (/^!=/.test(self.operator)) return self.left.condition;
+                    }
+                }
             }
         }
         self = self.lift_sequences(compressor);
@@ -1807,11 +2013,6 @@ merge(Compressor.prototype, {
             }
             break;
         }
-        var exp = self.evaluate(compressor);
-        if (exp.length > 1) {
-            if (best_of(exp[0], self) !== self)
-                return exp[0];
-        }
         if (compressor.option("comparisons")) {
             if (!(compressor.parent() instanceof AST_Binary)
                 || compressor.parent() instanceof AST_Assign) {
@@ -1831,7 +2032,76 @@ merge(Compressor.prototype, {
             && self.left.operator == "+" && self.left.is_string(compressor)) {
             return self.left;
         }
-        return self;
+        if (compressor.option("evaluate")) {
+            if (self.operator == "+") {
+                if (self.left instanceof AST_Constant
+                    && self.right instanceof AST_Binary
+                    && self.right.operator == "+"
+                    && self.right.left instanceof AST_Constant
+                    && self.right.is_string(compressor)) {
+                    self = make_node(AST_Binary, self, {
+                        operator: "+",
+                        left: make_node(AST_String, null, {
+                            value: "" + self.left.getValue() + self.right.left.getValue(),
+                            start: self.left.start,
+                            end: self.right.left.end
+                        }),
+                        right: self.right.right
+                    });
+                }
+                if (self.right instanceof AST_Constant
+                    && self.left instanceof AST_Binary
+                    && self.left.operator == "+"
+                    && self.left.right instanceof AST_Constant
+                    && self.left.is_string(compressor)) {
+                    self = make_node(AST_Binary, self, {
+                        operator: "+",
+                        left: self.left.left,
+                        right: make_node(AST_String, null, {
+                            value: "" + self.left.right.getValue() + self.right.getValue(),
+                            start: self.left.right.start,
+                            end: self.right.end
+                        })
+                    });
+                }
+                if (self.left instanceof AST_Binary
+                    && self.left.operator == "+"
+                    && self.left.is_string(compressor)
+                    && self.left.right instanceof AST_Constant
+                    && self.right instanceof AST_Binary
+                    && self.right.operator == "+"
+                    && self.right.left instanceof AST_Constant
+                    && self.right.is_string(compressor)) {
+                    self = make_node(AST_Binary, self, {
+                        operator: "+",
+                        left: make_node(AST_Binary, self.left, {
+                            operator: "+",
+                            left: self.left.left,
+                            right: make_node(AST_String, null, {
+                                value: "" + self.left.right.getValue() + self.right.left.getValue(),
+                                start: self.left.right.start,
+                                end: self.right.left.end
+                            })
+                        }),
+                        right: self.right.right
+                    });
+                }
+            }
+        }
+        // x * (y * z)  ==>  x * y * z
+        if (self.right instanceof AST_Binary
+            && self.right.operator == self.operator
+            && (self.operator == "*" || self.operator == "&&" || self.operator == "||"))
+        {
+            self.left = make_node(AST_Binary, self.left, {
+                operator : self.operator,
+                left     : self.left,
+                right    : self.right.left
+            });
+            self.right = self.right.right;
+            return self.transform(compressor);
+        }
+        return self.evaluate(compressor)[0];
     });
 
     OPT(AST_SymbolRef, function(self, compressor){
@@ -1965,8 +2235,7 @@ merge(Compressor.prototype, {
         var prop = self.property;
         if (prop instanceof AST_String && compressor.option("properties")) {
             prop = prop.getValue();
-            if (compressor.option("screw_ie8") && RESERVED_WORDS(prop)
-                || !(RESERVED_WORDS(prop)) && is_identifier_string(prop)) {
+            if (RESERVED_WORDS(prop) ? compressor.option("screw_ie8") : is_identifier_string(prop)) {
                 return make_node(AST_Dot, self, {
                     expression : self.expression,
                     property   : prop

lib/output.js

@@ -54,13 +54,14 @@ function OutputStream(options) {
         inline_script : false,
         width         : 80,
         max_line_len  : 32000,
-        ie_proof      : true,
         beautify      : false,
         source_map    : null,
         bracketize    : false,
         semicolons    : true,
         comments      : false,
-        preserve_line : false
+        preserve_line : false,
+        screw_ie8     : false,
+        preamble      : null,
     }, true);
 
     var indentation = 0;
@@ -95,7 +96,7 @@ function OutputStream(options) {
               case "\u2029": return "\\u2029";
               case '"': ++dq; return '"';
               case "'": ++sq; return "'";
-              case "\0": return "\\0";
+              case "\0": return "\\x00";
             }
             return s;
         });
@@ -299,6 +300,10 @@ function OutputStream(options) {
         return OUTPUT;
     };
 
+    if (options.preamble) {
+        print(options.preamble.replace(/\r\n?|[\n\u2028\u2029]|\s*$/g, "\n"));
+    }
+
     var stack = [];
     return {
         get             : get,
@@ -350,18 +355,17 @@ function OutputStream(options) {
 
     AST_Node.DEFMETHOD("print", function(stream, force_parens){
         var self = this, generator = self._codegen;
-        stream.push_node(self);
-        if (force_parens || self.needs_parens(stream)) {
-            stream.with_parens(function(){
-                self.add_comments(stream);
-                self.add_source_map(stream);
-                generator(self, stream);
-            });
-        } else {
+        function doit() {
             self.add_comments(stream);
             self.add_source_map(stream);
             generator(self, stream);
         }
+        stream.push_node(self);
+        if (force_parens || self.needs_parens(stream)) {
+            stream.with_parens(doit);
+        } else {
+            doit();
+        }
         stream.pop_node();
     });
 
@@ -379,14 +383,15 @@ function OutputStream(options) {
             var start = self.start;
             if (start && !start._comments_dumped) {
                 start._comments_dumped = true;
-                var comments = start.comments_before;
+                var comments = start.comments_before || [];
 
                 // XXX: ugly fix for https://github.com/mishoo/UglifyJS2/issues/112
                 //      if this node is `return` or `throw`, we cannot allow comments before
                 //      the returned or thrown value.
-                if (self instanceof AST_Exit &&
-                    self.value && self.value.start.comments_before.length > 0) {
-                    comments = (comments || []).concat(self.value.start.comments_before);
+                if (self instanceof AST_Exit && self.value
+                    && self.value.start.comments_before
+                    && self.value.start.comments_before.length > 0) {
+                    comments = comments.concat(self.value.start.comments_before);
                     self.value.start.comments_before = [];
                 }
 
@@ -400,7 +405,7 @@ function OutputStream(options) {
                     });
                 }
                 comments.forEach(function(c){
-                    if (c.type == "comment1") {
+                    if (/comment[134]/.test(c.type)) {
                         output.print("//" + c.value + "\n");
                         output.indent();
                     }
@@ -476,11 +481,7 @@ function OutputStream(options) {
             var so = this.operator, sp = PRECEDENCE[so];
             if (pp > sp
                 || (pp == sp
-                    && this === p.right
-                    && !(so == po &&
-                         (so == "*" ||
-                          so == "&&" ||
-                          so == "||")))) {
+                    && this === p.right)) {
                 return true;
             }
         }
@@ -507,8 +508,17 @@ function OutputStream(options) {
     });
 
     PARENS(AST_Call, function(output){
-        var p = output.parent();
-        return p instanceof AST_New && p.expression === this;
+        var p = output.parent(), p1;
+        if (p instanceof AST_New && p.expression === this)
+            return true;
+
+        // workaround for Safari bug.
+        // https://bugs.webkit.org/show_bug.cgi?id=123506
+        return this.expression instanceof AST_Function
+            && p instanceof AST_PropAccess
+            && p.expression === this
+            && (p1 = output.parent(1)) instanceof AST_Assign
+            && p1.left === p;
     });
 
     PARENS(AST_New, function(output){
@@ -757,7 +767,7 @@ function OutputStream(options) {
         if (!self.body)
             return output.force_semicolon();
         if (self.body instanceof AST_Do
-            && output.option("ie_proof")) {
+            && !output.option("screw_ie8")) {
             // https://github.com/mishoo/UglifyJS/issues/#issue/57 IE
             // croaks with "syntax error" on code like this: if (foo)
             // do ... while(cond); else ...  we need block brackets
@@ -990,7 +1000,18 @@ function OutputStream(options) {
         self.left.print(output);
         output.space();
         output.print(self.operator);
-        output.space();
+        if (self.operator == "<"
+            && self.right instanceof AST_UnaryPrefix
+            && self.right.operator == "!"
+            && self.right.expression instanceof AST_UnaryPrefix
+            && self.right.expression.operator == "--") {
+            // space is mandatory to avoid outputting <!--
+            // http://javascript.spec.whatwg.org/#comment-syntax
+            output.print(" ");
+        } else {
+            // the space is optional depending on "beautify"
+            output.space();
+        }
         self.right.print(output);
     });
     DEFPRINT(AST_Conditional, function(self, output){
@@ -1012,6 +1033,11 @@ function OutputStream(options) {
             a.forEach(function(exp, i){
                 if (i) output.comma();
                 exp.print(output);
+                // If the final element is a hole, we need to make sure it
+                // doesn't look like a trailing comma, by inserting an actual
+                // trailing comma.
+                if (i === len - 1 && exp instanceof AST_Hole)
+                  output.comma();
             });
             if (len > 0) output.space();
         });
@@ -1039,20 +1065,24 @@ function OutputStream(options) {
                     && +key + "" == key)
                    && parseFloat(key) >= 0) {
             output.print(make_num(key));
-        } else if (!is_identifier(key)) {
-            output.print_string(key);
-        } else {
+        } else if (RESERVED_WORDS(key) ? output.option("screw_ie8") : is_identifier_string(key)) {
             output.print_name(key);
+        } else {
+            output.print_string(key);
         }
         output.colon();
         self.value.print(output);
     });
     DEFPRINT(AST_ObjectSetter, function(self, output){
         output.print("set");
+        output.space();
+        self.key.print(output);
         self.value._do_print(output, true);
     });
     DEFPRINT(AST_ObjectGetter, function(self, output){
         output.print("get");
+        output.space();
+        self.key.print(output);
         self.value._do_print(output, true);
     });
     DEFPRINT(AST_Symbol, function(self, output){
@@ -1119,7 +1149,7 @@ function OutputStream(options) {
             if (p instanceof AST_Statement && p.body === node)
                 return true;
             if ((p instanceof AST_Seq           && p.car === node        ) ||
-                (p instanceof AST_Call          && p.expression === node ) ||
+                (p instanceof AST_Call          && p.expression === node && !(p instanceof AST_New) ) ||
                 (p instanceof AST_Dot           && p.expression === node ) ||
                 (p instanceof AST_Sub           && p.expression === node ) ||
                 (p instanceof AST_Conditional   && p.condition === node  ) ||

lib/parse.js

@@ -168,7 +168,10 @@ function is_identifier_char(ch) {
 };
 
 function is_identifier_string(str){
-    for (var i = str.length; --i >= 0;) {
+    var i = str.length;
+    if (i == 0) return false;
+    if (!is_identifier_start(str.charCodeAt(0))) return false;
+    while (--i >= 0) {
         if (!is_identifier_char(str.charAt(i)))
             return false;
     }
@@ -207,7 +210,7 @@ function is_token(token, type, val) {
 
 var EX_EOF = {};
 
-function tokenizer($TEXT, filename) {
+function tokenizer($TEXT, filename, html5_comments) {
 
     var S = {
         text            : $TEXT.replace(/\r\n?|[\n\u2028\u2029]/g, "\n").replace(/\uFEFF/g, ''),
@@ -239,6 +242,14 @@ function tokenizer($TEXT, filename) {
         return ch;
     };
 
+    function forward(i) {
+        while (i-- > 0) next();
+    };
+
+    function looking_at(str) {
+        return S.text.substr(S.pos, str.length) == str;
+    };
+
     function find(what, signal_eof) {
         var pos = S.text.indexOf(what, S.pos);
         if (signal_eof && pos == -1) throw EX_EOF;
@@ -251,10 +262,12 @@ function tokenizer($TEXT, filename) {
         S.tokpos = S.pos;
     };
 
+    var prev_was_dot = false;
     function token(type, value, is_comment) {
-        S.regex_allowed = ((type == "operator" && !UNARY_POSTFIX[value]) ||
+        S.regex_allowed = ((type == "operator" && !UNARY_POSTFIX(value)) ||
                            (type == "keyword" && KEYWORDS_BEFORE_EXPRESSION(value)) ||
                            (type == "punc" && PUNC_BEFORE_EXPRESSION(value)));
+        prev_was_dot = (type == "punc" && value == ".");
         var ret = {
             type   : type,
             value  : value,
@@ -376,8 +389,8 @@ function tokenizer($TEXT, filename) {
         return token("string", ret);
     });
 
-    function read_line_comment() {
-        next();
+    function skip_line_comment(type) {
+        var regex_allowed = S.regex_allowed;
         var i = find("\n"), ret;
         if (i == -1) {
             ret = S.text.substr(S.pos);
@@ -386,11 +399,13 @@ function tokenizer($TEXT, filename) {
             ret = S.text.substring(S.pos, i);
             S.pos = i;
         }
-        return token("comment1", ret, true);
+        S.comments_before.push(token(type, ret, true));
+        S.regex_allowed = regex_allowed;
+        return next_token();
     };
 
-    var read_multiline_comment = with_eof_error("Unterminated multiline comment", function(){
-        next();
+    var skip_multiline_comment = with_eof_error("Unterminated multiline comment", function(){
+        var regex_allowed = S.regex_allowed;
         var i = find("*/", true);
         var text = S.text.substring(S.pos, i);
         var a = text.split("\n"), n = a.length;
@@ -400,8 +415,11 @@ function tokenizer($TEXT, filename) {
         if (n > 1) S.col = a[n - 1].length;
         else S.col += a[n - 1].length;
         S.col += 2;
-        S.newline_before = S.newline_before || text.indexOf("\n") >= 0;
-        return token("comment2", text, true);
+        var nlb = S.newline_before = S.newline_before || text.indexOf("\n") >= 0;
+        S.comments_before.push(token("comment2", text, true));
+        S.regex_allowed = regex_allowed;
+        S.newline_before = nlb;
+        return next_token();
     });
 
     function read_name() {
@@ -465,16 +483,13 @@ function tokenizer($TEXT, filename) {
 
     function handle_slash() {
         next();
-        var regex_allowed = S.regex_allowed;
         switch (peek()) {
           case "/":
-            S.comments_before.push(read_line_comment());
-            S.regex_allowed = regex_allowed;
-            return next_token();
+            next();
+            return skip_line_comment("comment1");
           case "*":
-            S.comments_before.push(read_multiline_comment());
-            S.regex_allowed = regex_allowed;
-            return next_token();
+            next();
+            return skip_multiline_comment();
         }
         return S.regex_allowed ? read_regexp("") : read_operator("/");
     };
@@ -488,6 +503,7 @@ function tokenizer($TEXT, filename) {
 
     function read_word() {
         var word = read_name();
+        if (prev_was_dot) return token("name", word);
         return KEYWORDS_ATOM(word) ? token("atom", word)
             : !KEYWORDS(word) ? token("name", word)
             : OPERATORS(word) ? token("operator", word)
@@ -510,6 +526,16 @@ function tokenizer($TEXT, filename) {
             return read_regexp(force_regexp);
         skip_whitespace();
         start_token();
+        if (html5_comments) {
+            if (looking_at("<!--")) {
+                forward(4);
+                return skip_line_comment("comment3");
+            }
+            if (looking_at("-->") && S.newline_before) {
+                forward(3);
+                return skip_line_comment("comment4");
+            }
+        }
         var ch = peek();
         if (!ch) return token("eof");
         var code = ch.charCodeAt(0);
@@ -553,10 +579,10 @@ var UNARY_POSTFIX = makePredicate([ "--", "++" ]);
 var ASSIGNMENT = makePredicate([ "=", "+=", "-=", "/=", "*=", "%=", ">>=", "<<=", ">>>=", "|=", "^=", "&=" ]);
 
 var PRECEDENCE = (function(a, ret){
-    for (var i = 0, n = 1; i < a.length; ++i, ++n) {
+    for (var i = 0; i < a.length; ++i) {
         var b = a[i];
         for (var j = 0; j < b.length; ++j) {
-            ret[b[j]] = n;
+            ret[b[j]] = i + 1;
         }
     }
     return ret;
@@ -585,13 +611,18 @@ var ATOMIC_START_TOKEN = array_to_hash([ "atom", "num", "string", "regexp", "nam
 function parse($TEXT, options) {
 
     options = defaults(options, {
-        strict   : false,
-        filename : null,
-        toplevel : null
+        strict         : false,
+        filename       : null,
+        toplevel       : null,
+        expression     : false,
+        html5_comments : true,
     });
 
     var S = {
-        input         : typeof $TEXT == "string" ? tokenizer($TEXT, options.filename) : $TEXT,
+        input         : (typeof $TEXT == "string"
+                         ? tokenizer($TEXT, options.filename,
+                                     options.html5_comments)
+                         : $TEXT),
         token         : null,
         prev          : null,
         peeked        : null,
@@ -684,12 +715,16 @@ function parse($TEXT, options) {
         };
     };
 
-    var statement = embed_tokens(function() {
-        var tmp;
+    function handle_regexp() {
         if (is("operator", "/") || is("operator", "/=")) {
             S.peeked = null;
             S.token = S.input(S.token.value.substr(1)); // force regexp
         }
+    };
+
+    var statement = embed_tokens(function() {
+        var tmp;
+        handle_regexp();
         switch (S.token.type) {
           case "string":
             var dir = S.in_directives, stat = simple_statement();
@@ -754,7 +789,7 @@ function parse($TEXT, options) {
                 return for_();
 
               case "function":
-                return function_(true);
+                return function_(AST_Defun);
 
               case "if":
                 return if_();
@@ -817,6 +852,18 @@ function parse($TEXT, options) {
         S.labels.push(label);
         var stat = statement();
         S.labels.pop();
+        if (!(stat instanceof AST_IterationStatement)) {
+            // check for `continue` that refers to this label.
+            // those should be reported as syntax errors.
+            // https://github.com/mishoo/UglifyJS2/issues/287
+            label.references.forEach(function(ref){
+                if (ref instanceof AST_Continue) {
+                    ref = ref.label.start;
+                    croak("Continue label `" + label.name + "` refers to non-IterationStatement.",
+                          ref.line, ref.col, ref.pos);
+                }
+            });
+        }
         return new AST_LabeledStatement({ body: stat, label: label });
     };
 
@@ -825,18 +872,22 @@ function parse($TEXT, options) {
     };
 
     function break_cont(type) {
-        var label = null;
+        var label = null, ldef;
         if (!can_insert_semicolon()) {
             label = as_symbol(AST_LabelRef, true);
         }
         if (label != null) {
-            if (!find_if(function(l){ return l.name == label.name }, S.labels))
+            ldef = find_if(function(l){ return l.name == label.name }, S.labels);
+            if (!ldef)
                 croak("Undefined label " + label.name);
+            label.thedef = ldef;
         }
         else if (S.in_loop == 0)
             croak(type.TYPE + " not inside a loop or switch");
         semicolon();
-        return new type({ label: label });
+        var stat = new type({ label: label });
+        if (ldef) ldef.references.push(stat);
+        return stat;
     };
 
     function for_() {
@@ -882,19 +933,12 @@ function parse($TEXT, options) {
         });
     };
 
-    var function_ = function(in_statement, ctor) {
-        var is_accessor = ctor === AST_Accessor;
-        var name = (is("name") ? as_symbol(in_statement
-                                           ? AST_SymbolDefun
-                                           : is_accessor
-                                           ? AST_SymbolAccessor
-                                           : AST_SymbolLambda)
-                    : is_accessor && (is("string") || is("num")) ? as_atom_node()
-                    : null);
+    var function_ = function(ctor) {
+        var in_statement = ctor === AST_Defun;
+        var name = is("name") ? as_symbol(in_statement ? AST_SymbolDefun : AST_SymbolLambda) : null;
         if (in_statement && !name)
             unexpected();
         expect("(");
-        if (!ctor) ctor = in_statement ? AST_Defun : AST_Function;
         return new ctor({
             name: name,
             argnames: (function(first, a){
@@ -1065,7 +1109,9 @@ function parse($TEXT, options) {
         var tok = S.token, ret;
         switch (tok.type) {
           case "name":
-            return as_symbol(AST_SymbolRef);
+          case "keyword":
+            ret = _make_symbol(AST_SymbolRef);
+            break;
           case "num":
             ret = new AST_Number({ start: tok, end: tok, value: tok.value });
             break;
@@ -1116,7 +1162,7 @@ function parse($TEXT, options) {
         }
         if (is("keyword", "function")) {
             next();
-            var func = function_(false);
+            var func = function_(AST_Function);
             func.start = start;
             func.end = prev();
             return subscripts(func, allow_calls);
@@ -1164,8 +1210,8 @@ function parse($TEXT, options) {
                 if (name == "get") {
                     a.push(new AST_ObjectGetter({
                         start : start,
-                        key   : name,
-                        value : function_(false, AST_Accessor),
+                        key   : as_atom_node(),
+                        value : function_(AST_Accessor),
                         end   : prev()
                     }));
                     continue;
@@ -1173,8 +1219,8 @@ function parse($TEXT, options) {
                 if (name == "set") {
                     a.push(new AST_ObjectSetter({
                         start : start,
-                        key   : name,
-                        value : function_(false, AST_Accessor),
+                        key   : as_atom_node(),
+                        value : function_(AST_Accessor),
                         end   : prev()
                     }));
                     continue;
@@ -1222,17 +1268,21 @@ function parse($TEXT, options) {
         }
     };
 
+    function _make_symbol(type) {
+        var name = S.token.value;
+        return new (name == "this" ? AST_This : type)({
+            name  : String(name),
+            start : S.token,
+            end   : S.token
+        });
+    };
+
     function as_symbol(type, noerror) {
         if (!is("name")) {
             if (!noerror) croak("Name expected");
             return null;
         }
-        var name = S.token.value;
-        var sym = new (name == "this" ? AST_This : type)({
-            name  : String(S.token.value),
-            start : S.token,
-            end   : S.token
-        });
+        var sym = _make_symbol(type);
         next();
         return sym;
     };
@@ -1275,6 +1325,7 @@ function parse($TEXT, options) {
         var start = S.token;
         if (is("operator") && UNARY_PREFIX(start.value)) {
             next();
+            handle_regexp();
             var ex = make_unary(AST_UnaryPrefix, start.value, maybe_unary(allow_calls));
             ex.start = start;
             ex.end = prev();
@@ -1338,15 +1389,8 @@ function parse($TEXT, options) {
 
     function is_assignable(expr) {
         if (!options.strict) return true;
-        switch (expr[0]+"") {
-          case "dot":
-          case "sub":
-          case "new":
-          case "call":
-            return true;
-          case "name":
-            return expr[1] != "this";
-        }
+        if (expr instanceof AST_This) return false;
+        return (expr instanceof AST_PropAccess || expr instanceof AST_Symbol);
     };
 
     var maybe_assign = function(no_in) {
@@ -1390,6 +1434,10 @@ function parse($TEXT, options) {
         return ret;
     };
 
+    if (options.expression) {
+        return expression(true);
+    }
+
     return (function(){
         var start = S.token;
         var body = [];

lib/scope.js

@@ -64,38 +64,35 @@ SymbolDef.prototype = {
     mangle: function(options) {
         if (!this.mangled_name && !this.unmangleable(options)) {
             var s = this.scope;
-            if (this.orig[0] instanceof AST_SymbolLambda && !options.screw_ie8)
+            if (!options.screw_ie8 && this.orig[0] instanceof AST_SymbolLambda)
                 s = s.parent_scope;
-            this.mangled_name = s.next_mangled(options);
+            this.mangled_name = s.next_mangled(options, this);
         }
     }
 };
 
-AST_Toplevel.DEFMETHOD("figure_out_scope", function(){
-    // This does what ast_add_scope did in UglifyJS v1.
-    //
-    // Part of it could be done at parse time, but it would complicate
-    // the parser (and it's already kinda complex).  It's also worth
-    // having it separated because we might need to call it multiple
-    // times on the same tree.
+AST_Toplevel.DEFMETHOD("figure_out_scope", function(options){
+    options = defaults(options, {
+        screw_ie8: false
+    });
 
     // 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 nesting = 0;
     var tw = new TreeWalker(function(node, descend){
         if (node instanceof AST_Scope) {
             node.init_scope_vars(nesting);
             var save_scope = node.parent_scope = scope;
-            var save_labels = labels;
-            ++nesting;
+            var save_defun = defun;
+            if (!(node instanceof AST_Catch)) {
+                defun = node;
+            }
             scope = node;
-            labels = new Dictionary();
-            descend();
-            labels = save_labels;
+            ++nesting; descend(); --nesting;
             scope = save_scope;
-            --nesting;
+            defun = save_defun;
             return true;        // don't descend again in TreeWalker
         }
         if (node instanceof AST_Directive) {
@@ -108,24 +105,11 @@ AST_Toplevel.DEFMETHOD("figure_out_scope", function(){
                 s.uses_with = true;
             return;
         }
-        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_Symbol) {
             node.scope = scope;
         }
-        if (node instanceof AST_Label) {
-            node.thedef = node;
-            node.init_scope_vars();
-        }
         if (node instanceof AST_SymbolLambda) {
-            scope.def_function(node);
+            defun.def_function(node);
         }
         else if (node instanceof AST_SymbolDefun) {
             // Careful here, the scope where this should be defined is
@@ -133,31 +117,17 @@ AST_Toplevel.DEFMETHOD("figure_out_scope", function(){
             // scope when we encounter the AST_Defun node (which is
             // instanceof AST_Scope) but we get to the symbol a bit
             // later.
-            (node.scope = scope.parent_scope).def_function(node);
+            (node.scope = defun.parent_scope).def_function(node);
         }
         else if (node instanceof AST_SymbolVar
                  || node instanceof AST_SymbolConst) {
-            var def = scope.def_variable(node);
+            var def = defun.def_variable(node);
             def.constant = node instanceof AST_SymbolConst;
             def.init = tw.parent().value;
         }
         else if (node instanceof AST_SymbolCatch) {
-            // XXX: this is wrong according to ECMA-262 (12.4).  the
-            // `catch` argument name should be visible only inside the
-            // catch block.  For a quick fix AST_Catch should inherit
-            // from AST_Scope.  Keeping it this way because of IE,
-            // which doesn't obey the standard. (it introduces the
-            // identifier in the enclosing scope)
-            scope.def_variable(node);
-        }
-        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;
+            (options.screw_ie8 ? scope : defun)
+                .def_variable(node);
         }
     });
     self.walk(tw);
@@ -173,10 +143,6 @@ AST_Toplevel.DEFMETHOD("figure_out_scope", function(){
             func = prev_func;
             return true;
         }
-        if (node instanceof AST_LabelRef) {
-            node.reference();
-            return true;
-        }
         if (node instanceof AST_SymbolRef) {
             var name = node.name;
             var sym = node.scope.find_variable(name);
@@ -187,6 +153,7 @@ AST_Toplevel.DEFMETHOD("figure_out_scope", function(){
                 } else {
                     g = new SymbolDef(self, globals.size(), node);
                     g.undeclared = true;
+                    g.global = true;
                     globals.set(name, g);
                 }
                 node.thedef = g;
@@ -194,7 +161,7 @@ AST_Toplevel.DEFMETHOD("figure_out_scope", function(){
                     for (var s = node.scope; s && !s.uses_eval; s = s.parent_scope)
                         s.uses_eval = true;
                 }
-                if (name == "arguments") {
+                if (func && name == "arguments") {
                     func.uses_arguments = true;
                 }
             } else {
@@ -240,14 +207,6 @@ AST_SymbolRef.DEFMETHOD("reference", function() {
     this.frame = this.scope.nesting - def.scope.nesting;
 });
 
-AST_Label.DEFMETHOD("init_scope_vars", function(){
-    this.references = [];
-});
-
-AST_LabelRef.DEFMETHOD("reference", function(){
-    this.thedef.references.push(this);
-});
-
 AST_Scope.DEFMETHOD("find_variable", function(name){
     if (name instanceof AST_Symbol) name = name.name;
     return this.variables.get(name)
@@ -293,6 +252,19 @@ AST_Scope.DEFMETHOD("next_mangled", function(options){
     }
 });
 
+AST_Function.DEFMETHOD("next_mangled", function(options, def){
+    // #179, #326
+    // in Safari strict mode, something like (function x(x){...}) is a syntax error;
+    // a function expression's argument cannot shadow the function expression's name
+
+    var tricky_def = def.orig[0] instanceof AST_SymbolFunarg && this.name && this.name.definition();
+    while (true) {
+        var name = AST_Lambda.prototype.next_mangled.call(this, options, def);
+        if (!(tricky_def && tricky_def.mangled_name == name))
+            return name;
+    }
+});
+
 AST_Scope.DEFMETHOD("references", function(sym){
     if (sym instanceof AST_Symbol) sym = sym.definition();
     return this.enclosed.indexOf(sym) < 0 ? null : sym;

lib/transform.js

@@ -44,7 +44,6 @@
 "use strict";
 
 // Tree transformer helpers.
-// XXX: eventually I should refactor the compressor to use this infrastructure.
 
 function TreeTransformer(before, after) {
     TreeWalker.call(this);
@@ -160,6 +159,7 @@ TreeTransformer.prototype = new TreeWalker;
     });
 
     _(AST_VarDef, function(self, tw){
+        self.name = self.name.transform(tw);
         if (self.value) self.value = self.value.transform(tw);
     });
 

lib/utils.js

@@ -86,12 +86,16 @@ function DefaultsError(msg, defs) {
     this.defs = defs;
 };
 
+DefaultsError.croak = function(msg, defs) {
+    throw new DefaultsError(msg, defs);
+};
+
 function defaults(args, defs, croak) {
     if (args === true)
         args = {};
     var ret = args || {};
     if (croak) for (var i in ret) if (ret.hasOwnProperty(i) && !defs.hasOwnProperty(i))
-        throw new DefaultsError("`" + i + "` is not a supported option", defs);
+        DefaultsError.croak("`" + i + "` is not a supported option", defs);
     for (var i in defs) if (defs.hasOwnProperty(i)) {
         ret[i] = (args && args.hasOwnProperty(i)) ? args[i] : defs[i];
     }
@@ -245,6 +249,13 @@ function makePredicate(words) {
     return new Function("str", f);
 };
 
+function all(array, predicate) {
+    for (var i = array.length; --i >= 0;)
+        if (!predicate(array[i]))
+            return false;
+    return true;
+};
+
 function Dictionary() {
     this._values = Object.create(null);
     this._size = 0;

package.json

@@ -3,21 +3,25 @@
     "description": "JavaScript parser, mangler/compressor and beautifier toolkit",
     "homepage": "http://lisperator.net/uglifyjs",
     "main": "tools/node.js",
-    "version": "2.3.1",
+    "version": "2.4.6",
     "engines": { "node" : ">=0.4.0" },
     "maintainers": [{
         "name": "Mihai Bazon",
         "email": "mihai.bazon@gmail.com",
         "web": "http://lisperator.net/"
     }],
-    "repositories": [{
+    "repository": {
         "type": "git",
         "url": "https://github.com/mishoo/UglifyJS2.git"
-    }],
+    },
     "dependencies": {
         "async"      : "~0.2.6",
         "source-map" : "~0.1.7",
-        "optimist"   : "~0.3.5"
+        "optimist"   : "~0.3.5",
+        "uglify-to-browserify": "~1.0.0"
+    },
+    "browserify": {
+        "transform": [ "uglify-to-browserify" ]
     },
     "bin": {
         "uglifyjs" : "bin/uglifyjs"

test/compress/arrays.js

@@ -1,12 +1,74 @@
 holes_and_undefined: {
     input: {
+        w = [1,,];
         x = [1, 2, undefined];
         y = [1, , 2, ];
         z = [1, undefined, 3];
     }
     expect: {
+        w=[1,,];
         x=[1,2,void 0];
         y=[1,,2];
         z=[1,void 0,3];
     }
 }
+
+constant_join: {
+    options = {
+        unsafe   : true,
+        evaluate : true
+    };
+    input: {
+        var a = [ "foo", "bar", "baz" ].join("");
+        var a1 = [ "foo", "bar", "baz" ].join();
+        var b = [ "foo", 1, 2, 3, "bar" ].join("");
+        var c = [ boo(), "foo", 1, 2, 3, "bar", bar() ].join("");
+        var c1 = [ boo(), bar(), "foo", 1, 2, 3, "bar", bar() ].join("");
+        var c2 = [ 1, 2, "foo", "bar", baz() ].join("");
+        var d = [ "foo", 1 + 2 + "bar", "baz" ].join("-");
+        var e = [].join(foo + bar);
+        var f = [].join("");
+        var g = [].join("foo");
+    }
+    expect: {
+        var a = "foobarbaz";
+        var a1 = "foo,bar,baz";
+        var b = "foo123bar";
+        var c = boo() + "foo123bar" + bar();
+        var c1 = "" + boo() + bar() + "foo123bar" + bar();
+        var c2 = "12foobar" + baz();
+        var d = "foo-3bar-baz";
+        var e = [].join(foo + bar);
+        var f = "";
+        var g = "";
+    }
+}
+
+constant_join_2: {
+    options = {
+        unsafe   : true,
+        evaluate : true
+    };
+    input: {
+        var a = [ "foo", "bar", boo(), "baz", "x", "y" ].join("");
+        var b = [ "foo", "bar", boo(), "baz", "x", "y" ].join("-");
+        var c = [ "foo", "bar", boo(), "baz", "x", "y" ].join("really-long-separator");
+        var d = [ "foo", "bar", boo(),
+                  [ "foo", 1, 2, 3, "bar" ].join("+"),
+                  "baz", "x", "y" ].join("-");
+        var e = [ "foo", "bar", boo(),
+                  [ "foo", 1, 2, 3, "bar" ].join("+"),
+                  "baz", "x", "y" ].join("really-long-separator");
+        var f = [ "str", "str" + variable, "foo", "bar", "moo" + foo ].join("");
+    }
+    expect: {
+        var a = "foobar" + boo() + "bazxy";
+        var b = [ "foo-bar", boo(), "baz-x-y" ].join("-");
+        var c = [ "foo", "bar", boo(), "baz", "x", "y" ].join("really-long-separator");
+        var d = [ "foo-bar", boo(), "foo+1+2+3+bar-baz-x-y" ].join("-");
+        var e = [ "foo", "bar", boo(),
+                  "foo+1+2+3+bar",
+                  "baz", "x", "y" ].join("really-long-separator");
+        var f = "strstr" + variable + "foobarmoo" + foo;
+    }
+}

test/compress/concat-strings.js

@@ -0,0 +1,22 @@
+concat_1: {
+    options = {
+        evaluate: true
+    };
+    input: {
+        var a = "foo" + "bar" + x() + "moo" + "foo" + y() + "x" + "y" + "z" + q();
+        var b = "foo" + 1 + x() + 2 + "boo";
+        var c = 1 + x() + 2 + "boo";
+
+        // this CAN'T safely be shortened to 1 + x() + "5boo"
+        var d = 1 + x() + 2 + 3 + "boo";
+
+        var e = 1 + x() + 2 + "X" + 3 + "boo";
+    }
+    expect: {
+        var a = "foobar" + x() + "moofoo" + y() + "xyz" + q();
+        var b = "foo1" + x() + "2boo";
+        var c = 1 + x() + 2 + "boo";
+        var d = 1 + x() + 2 + 3 + "boo";
+        var e = 1 + x() + 2 + "X3boo";
+    }
+}

test/compress/drop-unused.js

@@ -95,3 +95,27 @@ unused_circular_references_3: {
         }
     }
 }
+
+unused_keep_setter_arg: {
+    options = { unused: true };
+    input: {
+        var x = {
+            _foo: null,
+            set foo(val) {
+            },
+            get foo() {
+                return this._foo;
+            }
+        }
+    }
+    expect: {
+        var x = {
+            _foo: null,
+            set foo(val) {
+            },
+            get foo() {
+                return this._foo;
+            }
+        }
+    }
+}

test/compress/issue-126.js

@@ -0,0 +1,24 @@
+concatenate_rhs_strings: {
+    options = {
+        evaluate: true,
+        unsafe: true,
+    }
+    input: {
+        foo(bar() + 123 + "Hello" + "World");
+        foo(bar() + (123 + "Hello") + "World");
+        foo((bar() + 123) + "Hello" + "World");
+        foo(bar() + 123 + "Hello" + "World" + ("Foo" + "Bar"));
+        foo("Foo" + "Bar" + bar() + 123 + "Hello" + "World" + ("Foo" + "Bar"));
+        foo("Hello" + bar() + 123 + "World");
+        foo(bar() + 'Foo' + (10 + parseInt('10')));
+    }
+    expect: {
+        foo(bar() + 123 + "HelloWorld");
+        foo(bar() + "123HelloWorld");
+        foo((bar() + 123) + "HelloWorld");
+        foo(bar() + 123 + "HelloWorldFooBar");
+        foo("FooBar" + bar() + "123HelloWorldFooBar");
+        foo("Hello" + bar() + "123World");
+        foo(bar() + 'Foo' + (10 + parseInt('10')));
+    }
+}

test/compress/issue-267.js

@@ -0,0 +1,11 @@
+issue_267: {
+    options = { comparisons: true };
+    input: {
+        x = a % b / b * c * 2;
+        x = a % b * 2
+    }
+    expect: {
+        x = a % b / b * c * 2;
+        x = a % b * 2;
+    }
+}

test/compress/issue-269.js

@@ -0,0 +1,66 @@
+issue_269_1: {
+	options = {unsafe: true};
+	input: {
+		f(
+			String(x),
+			Number(x),
+			Boolean(x),
+
+			String(),
+			Number(),
+			Boolean()
+		);
+	}
+	expect: {
+		f(
+			x + '', +x, !!x,
+			'', 0, false
+		);
+	}
+}
+
+issue_269_dangers: {
+	options = {unsafe: true};
+	input: {
+		f(
+			String(x, x),
+			Number(x, x),
+			Boolean(x, x)
+		);
+	}
+	expect: {
+		f(String(x, x), Number(x, x), Boolean(x, x));
+	}
+}
+
+issue_269_in_scope: {
+	options = {unsafe: true};
+	input: {
+		var String, Number, Boolean;
+		f(
+			String(x),
+			Number(x, x),
+			Boolean(x)
+		);
+	}
+	expect: {
+		var String, Number, Boolean;
+		f(String(x), Number(x, x), Boolean(x));
+	}
+}
+
+strings_concat: {
+	options = {unsafe: true};
+	input: {
+		f(
+			String(x + 'str'),
+			String('str' + x)
+		);
+	}
+	expect: {
+		f(
+			x + 'str',
+			'str' + x
+		);
+	}
+}

test/compress/negate-iife.js

@@ -0,0 +1,76 @@
+negate_iife_1: {
+    options = {
+        negate_iife: true
+    };
+    input: {
+        (function(){ stuff() })();
+    }
+    expect: {
+        !function(){ stuff() }();
+    }
+}
+
+negate_iife_2: {
+    options = {
+        negate_iife: true
+    };
+    input: {
+        (function(){ return {} })().x = 10; // should not transform this one
+    }
+    expect: {
+        (function(){ return {} })().x = 10;
+    }
+}
+
+negate_iife_3: {
+    options = {
+        negate_iife: true,
+    };
+    input: {
+        (function(){ return true })() ? console.log(true) : console.log(false);
+    }
+    expect: {
+        !function(){ return true }() ? console.log(false) : console.log(true);
+    }
+}
+
+negate_iife_3: {
+    options = {
+        negate_iife: true,
+        sequences: true
+    };
+    input: {
+        (function(){ return true })() ? console.log(true) : console.log(false);
+        (function(){
+            console.log("something");
+        })();
+    }
+    expect: {
+        !function(){ return true }() ? console.log(false) : console.log(true), function(){
+            console.log("something");
+        }();
+    }
+}
+
+negate_iife_4: {
+    options = {
+        negate_iife: true,
+        sequences: true,
+        conditionals: true,
+    };
+    input: {
+        if ((function(){ return true })()) {
+            console.log(true);
+        } else {
+            console.log(false);
+        }
+        (function(){
+            console.log("something");
+        })();
+    }
+    expect: {
+        !function(){ return true }() ? console.log(false) : console.log(true), function(){
+            console.log("something");
+        }();
+    }
+}

test/compress/properties.js

@@ -19,12 +19,16 @@ dot_properties: {
         a["if"] = "if";
         a["*"] = "asterisk";
         a["\u0EB3"] = "unicode";
+        a[""] = "whitespace";
+        a["1_1"] = "foo";
     }
     expect: {
         a.foo = "bar";
         a["if"] = "if";
         a["*"] = "asterisk";
         a.\u0EB3 = "unicode";
+        a[""] = "whitespace";
+        a["1_1"] = "foo";
     }
 }
 
@@ -38,11 +42,13 @@ dot_properties_es5: {
         a["if"] = "if";
         a["*"] = "asterisk";
         a["\u0EB3"] = "unicode";
+        a[""] = "whitespace";
     }
     expect: {
         a.foo = "bar";
         a.if = "if";
         a["*"] = "asterisk";
         a.\u0EB3 = "unicode";
+        a[""] = "whitespace";
     }
 }

test/compress/sequences.js

@@ -101,10 +101,12 @@ lift_sequences_1: {
 lift_sequences_2: {
     options = { sequences: true, evaluate: true };
     input: {
-        q = 1 + (foo(), bar(), 5) + 7 * (5 / (3 - (a(), (QW=ER), c(), 2))) - (x(), y(), 5);
+        foo.x = (foo = {}, 10);
+        bar = (bar = {}, 10);
     }
     expect: {
-        foo(), bar(), a(), QW = ER, c(), x(), y(), q = 36
+        foo.x = (foo = {}, 10),
+        bar = {}, bar = 10;
     }
 }
 

test/run-tests.js

@@ -7,8 +7,15 @@ var assert = require("assert");
 var sys = require("util");
 
 var tests_dir = path.dirname(module.filename);
+var failures = 0;
+var failed_files = {};
 
 run_compress_tests();
+if (failures) {
+    sys.error("\n!!! Failed " + failures + " test cases.");
+    sys.error("!!! " + Object.keys(failed_files).join(", "));
+    process.exit(1);
+}
 
 /* -----[ utils ]----- */
 
@@ -83,6 +90,8 @@ function run_compress_tests() {
                     output: output,
                     expected: expect
                 });
+                failures++;
+                failed_files[file] = 1;
             }
         }
         var tests = parse_test(path.resolve(dir, file));

tools/node.js

@@ -63,6 +63,8 @@ exports.minify = function(files, options) {
     if (typeof files == "string")
         files = [ files ];
 
+    UglifyJS.base54.reset();
+
     // 1. parse
     var toplevel = null;
     files.forEach(function(file){