From bbff7403fbf46f9ad92240ac213df8d30ef31b64 Mon Sep 17 00:00:00 2001 From: Florian Dold Date: Thu, 20 Sep 2018 02:56:13 +0200 Subject: update packages --- node_modules/uglify-js/lib/compress.js | 4807 +++++++++++++++++++++----------- 1 file changed, 3151 insertions(+), 1656 deletions(-) (limited to 'node_modules/uglify-js/lib/compress.js') diff --git a/node_modules/uglify-js/lib/compress.js b/node_modules/uglify-js/lib/compress.js index ce0fbdd56..df33a5c39 100644 --- a/node_modules/uglify-js/lib/compress.js +++ b/node_modules/uglify-js/lib/compress.js @@ -48,49 +48,51 @@ function Compressor(options, false_by_default) { return new Compressor(options, false_by_default); TreeTransformer.call(this, this.before, this.after); this.options = defaults(options, { - booleans : !false_by_default, - cascade : !false_by_default, - collapse_vars : !false_by_default, - comparisons : !false_by_default, - conditionals : !false_by_default, - dead_code : !false_by_default, - drop_console : false, - drop_debugger : !false_by_default, - evaluate : !false_by_default, - expression : false, - global_defs : {}, - hoist_funs : !false_by_default, - hoist_props : !false_by_default, - hoist_vars : false, - ie8 : false, - if_return : !false_by_default, - inline : !false_by_default, - join_vars : !false_by_default, - keep_fargs : true, - keep_fnames : false, - keep_infinity : false, - loops : !false_by_default, - negate_iife : !false_by_default, - passes : 1, - properties : !false_by_default, - pure_getters : !false_by_default && "strict", - pure_funcs : null, - reduce_funcs : !false_by_default, - reduce_vars : !false_by_default, - sequences : !false_by_default, - side_effects : !false_by_default, - switches : !false_by_default, - top_retain : null, - toplevel : !!(options && options["top_retain"]), - typeofs : !false_by_default, - unsafe : false, - unsafe_comps : false, - unsafe_Func : false, - unsafe_math : false, - unsafe_proto : false, - unsafe_regexp : false, - unused : !false_by_default, - warnings : false, + arguments : !false_by_default, + booleans : !false_by_default, + collapse_vars : !false_by_default, + comparisons : !false_by_default, + conditionals : !false_by_default, + dead_code : !false_by_default, + directives : !false_by_default, + drop_console : false, + drop_debugger : !false_by_default, + evaluate : !false_by_default, + expression : false, + global_defs : false, + hoist_funs : false, + hoist_props : !false_by_default, + hoist_vars : false, + ie8 : false, + if_return : !false_by_default, + inline : !false_by_default, + join_vars : !false_by_default, + keep_fargs : true, + keep_fnames : false, + keep_infinity : false, + loops : !false_by_default, + negate_iife : !false_by_default, + passes : 1, + properties : !false_by_default, + pure_getters : !false_by_default && "strict", + pure_funcs : null, + reduce_funcs : !false_by_default, + reduce_vars : !false_by_default, + sequences : !false_by_default, + side_effects : !false_by_default, + switches : !false_by_default, + top_retain : null, + toplevel : !!(options && options["top_retain"]), + typeofs : !false_by_default, + unsafe : false, + unsafe_comps : false, + unsafe_Function : false, + unsafe_math : false, + unsafe_proto : false, + unsafe_regexp : false, + unsafe_undefined: false, + unused : !false_by_default, + warnings : false, }, true); var global_defs = this.options["global_defs"]; if (typeof global_defs == "object") for (var key in global_defs) { @@ -100,6 +102,7 @@ function Compressor(options, false_by_default) { }); } } + if (this.options["inline"] === true) this.options["inline"] = 3; var pure_funcs = this.options["pure_funcs"]; if (typeof pure_funcs == "function") { this.pure_funcs = pure_funcs; @@ -134,7 +137,7 @@ function Compressor(options, false_by_default) { var sequences = this.options["sequences"]; this.sequences_limit = sequences == 1 ? 800 : sequences | 0; this.warnings_produced = {}; -}; +} Compressor.prototype = new TreeTransformer; merge(Compressor.prototype, { @@ -145,33 +148,14 @@ merge(Compressor.prototype, { return true; return false; }, - in_boolean_context: function() { - if (!this.option("booleans")) return false; - var self = this.self(); - for (var i = 0, p; p = this.parent(i); i++) { - if (p instanceof AST_SimpleStatement - || p instanceof AST_Conditional && p.condition === self - || p instanceof AST_DWLoop && p.condition === self - || p instanceof AST_For && p.condition === self - || p instanceof AST_If && p.condition === self - || p instanceof AST_UnaryPrefix && p.operator == "!" && p.expression === self) { - return true; - } - if (p instanceof AST_Binary && (p.operator == "&&" || p.operator == "||") - || p instanceof AST_Conditional - || p.tail_node() === self) { - self = p; - } else { - return false; - } - } - }, compress: function(node) { + node = node.resolve_defines(this); if (this.option("expression")) { node.process_expression(true); } var passes = +this.options.passes || 1; - var last_count = 1 / 0; + var min_count = 1 / 0; + var stopping = false; var mangle = { ie8: this.option("ie8") }; for (var pass = 0; pass < passes; pass++) { node.figure_out_scope(mangle); @@ -183,9 +167,15 @@ merge(Compressor.prototype, { node.walk(new TreeWalker(function() { count++; })); - this.info("pass " + pass + ": last_count: " + last_count + ", count: " + count); - if (count >= last_count) break; - last_count = count; + this.info("pass " + pass + ": last_count: " + min_count + ", count: " + count); + if (count < min_count) { + min_count = count; + stopping = false; + } else if (stopping) { + break; + } else { + stopping = true; + } } } if (this.option("expression")) { @@ -213,11 +203,10 @@ merge(Compressor.prototype, { }, before: function(node, descend, in_list) { if (node._squeezed) return node; - var was_scope = false; - if (node instanceof AST_Scope) { - node = node.hoist_properties(this); - node = node.hoist_declarations(this); - was_scope = true; + var is_scope = node instanceof AST_Scope; + if (is_scope) { + node.hoist_properties(this); + node.hoist_declarations(this); } // Before https://github.com/mishoo/UglifyJS2/pull/1602 AST_Node.optimize() // would call AST_Node.transform() if a different instance of AST_Node is @@ -232,7 +221,7 @@ merge(Compressor.prototype, { // output and performance. descend(node, this); var opt = node.optimize(this); - if (was_scope && opt instanceof AST_Scope) { + if (is_scope) { opt.drop_unused(this); descend(opt, this); } @@ -241,24 +230,12 @@ merge(Compressor.prototype, { } }); -(function(){ - - function OPT(node, optimizer) { - node.DEFMETHOD("optimize", function(compressor){ - var self = this; - if (self._optimized) return self; - if (compressor.has_directive("use asm")) return self; - var opt = optimizer(self, compressor); - opt._optimized = true; - return opt; - }); - }; - - OPT(AST_Node, function(self, compressor){ +(function(OPT) { + OPT(AST_Node, function(self, compressor) { return self; }); - AST_Node.DEFMETHOD("equivalent_to", function(node){ + AST_Node.DEFMETHOD("equivalent_to", function(node) { return this.TYPE == node.TYPE && this.print_to_string() == node.print_to_string(); }); @@ -294,14 +271,12 @@ merge(Compressor.prototype, { if (index >= 0) { node.body[index] = node.body[index].transform(tt); } - } - if (node instanceof AST_If) { + } else if (node instanceof AST_If) { node.body = node.body.transform(tt); if (node.alternative) { node.alternative = node.alternative.transform(tt); } - } - if (node instanceof AST_With) { + } else if (node instanceof AST_With) { node.body = node.body.transform(tt); } return node; @@ -309,244 +284,147 @@ merge(Compressor.prototype, { self.transform(tt); }); - AST_Toplevel.DEFMETHOD("reset_opt_flags", function(compressor) { - var reduce_vars = compressor.option("reduce_vars"); - var unused = compressor.option("unused"); - // Stack of look-up tables to keep track of whether a `SymbolDef` has been - // properly assigned before use: - // - `push()` & `pop()` when visiting conditional branches - // - backup & restore via `save_ids` when visiting out-of-order sections - var safe_ids = Object.create(null); - var suppressor = new TreeWalker(function(node) { - if (!(node instanceof AST_Symbol)) return; - var d = node.definition(); - if (!d) return; - if (node instanceof AST_SymbolRef) d.references.push(node); - d.fixed = false; - }); - var in_loop = null; - var loop_ids = Object.create(null); - var tw = new TreeWalker(function(node, descend) { - node._squeezed = false; - node._optimized = false; - if (reduce_vars) { - if (node instanceof AST_Toplevel) node.globals.each(reset_def); - if (node instanceof AST_Scope) node.variables.each(reset_def); - if (node instanceof AST_SymbolRef) { - var d = node.definition(); - d.references.push(node); - var value; - if (d.fixed === undefined || !safe_to_read(d) || d.single_use == "m") { - d.fixed = false; - } else if (d.fixed) { - value = node.fixed_value(); - if (value && ref_once(d)) { - d.single_use = value instanceof AST_Lambda - || d.scope === node.scope && value.is_constant_expression(); - } else { - d.single_use = false; - } - if (is_modified(node, value, 0, is_immutable(value))) { - if (d.single_use) { - d.single_use = "m"; - } else { - d.fixed = false; - } - } - } - mark_escaped(d, node.scope, node, value, 0); - } - if (node instanceof AST_SymbolCatch) { - node.definition().fixed = false; - } - if (node instanceof AST_VarDef) { - var d = node.name.definition(); - if (d.fixed === undefined || safe_to_assign(d, node.value)) { - if (node.value) { - d.fixed = function() { - return node.value; - }; - loop_ids[d.id] = in_loop; - mark(d, false); - descend(); - } else { - d.fixed = null; - } - mark(d, true); - return true; - } else if (node.value) { - d.fixed = false; - } - } - if (node instanceof AST_Assign - && node.operator == "=" - && node.left instanceof AST_SymbolRef) { - var d = node.left.definition(); - if (safe_to_assign(d, node.right)) { - d.references.push(node.left); - d.fixed = function() { - return node.right; - }; - mark(d, false); - node.right.walk(tw); - mark(d, true); - return true; - } - } - if (node instanceof AST_Defun) { - node.inlined = false; - var d = node.name.definition(); - if (compressor.exposed(d) || safe_to_read(d)) { - d.fixed = false; - } else { - d.fixed = node; - loop_ids[d.id] = in_loop; - mark(d, true); - d.single_use = ref_once(d); - } - var save_ids = safe_ids; - safe_ids = Object.create(null); - descend(); - safe_ids = save_ids; - return true; - } - if (node instanceof AST_Function) { - node.inlined = false; - push(); - var iife; - if (!node.name - && (iife = tw.parent()) instanceof AST_Call - && iife.expression === node) { - // Virtually turn IIFE parameters into variable definitions: - // (function(a,b) {...})(c,d) => (function() {var a=c,b=d; ...})() - // So existing transformation rules can work on them. - node.argnames.forEach(function(arg, i) { - var d = arg.definition(); - if (!node.uses_arguments && d.fixed === undefined) { - d.fixed = function() { - return iife.args[i] || make_node(AST_Undefined, iife); - }; - loop_ids[d.id] = in_loop; - mark(d, true); - } else { - d.fixed = false; - } - }); - } - descend(); - pop(); - return true; - } - if (node instanceof AST_Accessor) { - push(); - descend(); - pop(); - return true; - } - if (node instanceof AST_Binary && lazy_op(node.operator)) { - node.left.walk(tw); - push(); - node.right.walk(tw); - pop(); - return true; - } - if (node instanceof AST_Conditional) { - node.condition.walk(tw); - push(); - node.consequent.walk(tw); - pop(); - push(); - node.alternative.walk(tw); - pop(); - return true; - } - if (node instanceof AST_If) { - node.condition.walk(tw); - push(); - node.body.walk(tw); - pop(); - if (node.alternative) { - push(); - node.alternative.walk(tw); - pop(); - } - return true; - } - if (node instanceof AST_DWLoop) { - var saved_loop = in_loop; - in_loop = node; - push(); - node.condition.walk(tw); - node.body.walk(tw); - pop(); - in_loop = saved_loop; - return true; - } - if (node instanceof AST_LabeledStatement) { - push(); - node.body.walk(tw); - pop(); - return true; - } - if (node instanceof AST_For) { - if (node.init) node.init.walk(tw); - var saved_loop = in_loop; - in_loop = node; - if (node.condition) { - push(); - node.condition.walk(tw); - pop(); - } - push(); - node.body.walk(tw); - pop(); - if (node.step) { - push(); - node.step.walk(tw); - pop(); - } - in_loop = saved_loop; - return true; - } - if (node instanceof AST_ForIn) { - node.init.walk(suppressor); - node.object.walk(tw); - var saved_loop = in_loop; - in_loop = node; - push(); - node.body.walk(tw); - pop(); - in_loop = saved_loop; - return true; + function read_property(obj, key) { + key = get_value(key); + if (key instanceof AST_Node) return; + var value; + if (obj instanceof AST_Array) { + var elements = obj.elements; + if (key == "length") return make_node_from_constant(elements.length, obj); + if (typeof key == "number" && key in elements) value = elements[key]; + } else if (obj instanceof AST_Object) { + key = "" + key; + var props = obj.properties; + for (var i = props.length; --i >= 0;) { + var prop = props[i]; + if (!(prop instanceof AST_ObjectKeyVal)) return; + if (!value && props[i].key === key) value = props[i].value; + } + } + return value instanceof AST_SymbolRef && value.fixed_value() || value; + } + + function is_modified(compressor, tw, node, value, level, immutable) { + var parent = tw.parent(level); + var lhs = is_lhs(node, parent); + if (lhs) return lhs; + if (!immutable + && parent instanceof AST_Call + && parent.expression === node + && !parent.is_expr_pure(compressor) + && (!(value instanceof AST_Function) + || !(parent instanceof AST_New) && value.contains_this())) { + return true; + } + if (parent instanceof AST_Array) { + return is_modified(compressor, tw, parent, parent, level + 1); + } + if (parent instanceof AST_ObjectKeyVal && node === parent.value) { + var obj = tw.parent(level + 1); + return is_modified(compressor, tw, obj, obj, level + 2); + } + if (parent instanceof AST_PropAccess && parent.expression === node) { + var prop = read_property(value, parent.property); + return !immutable && is_modified(compressor, tw, parent, prop, level + 1); + } + } + + (function(def) { + def(AST_Node, noop); + + function reset_def(tw, compressor, def) { + def.assignments = 0; + def.chained = false; + def.direct_access = false; + def.escaped = false; + def.fixed = !def.scope.pinned() + && !compressor.exposed(def) + && !(def.init instanceof AST_Function && def.init !== def.scope) + && def.init; + if (def.fixed instanceof AST_Defun && !all(def.references, function(ref) { + var scope = ref.scope; + do { + if (def.scope === scope) return true; + } while (scope instanceof AST_Function && (scope = scope.parent_scope)); + })) { + tw.defun_ids[def.id] = false; + } + def.recursive_refs = 0; + def.references = []; + def.should_replace = undefined; + def.single_use = undefined; + } + + function reset_variables(tw, compressor, scope) { + scope.variables.each(function(def) { + reset_def(tw, compressor, def); + if (def.fixed === null) { + def.safe_ids = tw.safe_ids; + mark(tw, def, true); + } else if (def.fixed) { + tw.loop_ids[def.id] = tw.in_loop; + mark(tw, def, true); } - if (node instanceof AST_Try) { - push(); - walk_body(node, tw); - pop(); - if (node.bcatch) { - push(); - node.bcatch.walk(tw); - pop(); + }); + scope.may_call_this = function() { + scope.may_call_this = noop; + if (!scope.contains_this()) return; + scope.functions.each(function(def) { + if (def.init instanceof AST_Defun && !(def.id in tw.defun_ids)) { + tw.defun_ids[def.id] = false; } - if (node.bfinally) node.bfinally.walk(tw); - return true; + }); + }; + } + + function mark_defun(tw, def) { + if (def.id in tw.defun_ids) { + var marker = tw.defun_ids[def.id]; + if (!marker) return; + var visited = tw.defun_visited[def.id]; + if (marker === tw.safe_ids) { + if (!visited) return def.fixed; + } else if (visited) { + def.init.enclosed.forEach(function(d) { + if (def.init.variables.get(d.name) === d) return; + if (!safe_to_read(tw, d)) d.fixed = false; + }); + } else { + tw.defun_ids[def.id] = false; } - if (node instanceof AST_SwitchBranch) { - push(); - descend(); - pop(); - return true; + } else { + if (!tw.in_loop) { + tw.defun_ids[def.id] = tw.safe_ids; + return def.fixed; } + tw.defun_ids[def.id] = false; } - }); - this.walk(tw); + } + + function walk_defuns(tw, scope) { + scope.functions.each(function(def) { + if (def.init instanceof AST_Defun && !tw.defun_visited[def.id]) { + tw.defun_ids[def.id] = tw.safe_ids; + def.init.walk(tw); + } + }); + } + + function push(tw) { + tw.safe_ids = Object.create(tw.safe_ids); + } - function mark(def, safe) { - safe_ids[def.id] = safe; + function pop(tw) { + tw.safe_ids = Object.getPrototypeOf(tw.safe_ids); } - function safe_to_read(def) { - if (safe_ids[def.id]) { + function mark(tw, def, safe) { + tw.safe_ids[def.id] = safe; + } + + function safe_to_read(tw, def) { + if (def.single_use == "m") return false; + if (tw.safe_ids[def.id]) { if (def.fixed == null) { var orig = def.orig[0]; if (orig instanceof AST_SymbolFunarg || orig.name == "arguments") return false; @@ -557,46 +435,30 @@ merge(Compressor.prototype, { return def.fixed instanceof AST_Defun; } - function safe_to_assign(def, value) { - if (!HOP(safe_ids, def.id)) return false; - if (!safe_to_read(def)) return false; + function safe_to_assign(tw, def, scope, value) { + if (def.fixed === undefined) return true; + if (def.fixed === null && def.safe_ids) { + def.safe_ids[def.id] = false; + delete def.safe_ids; + return true; + } + if (!HOP(tw.safe_ids, def.id)) return false; + if (!safe_to_read(tw, def)) return false; if (def.fixed === false) return false; - if (def.fixed != null && (!value || def.references.length > 0)) return false; - return !def.orig.some(function(sym) { - return sym instanceof AST_SymbolDefun - || sym instanceof AST_SymbolLambda; - }); - } - - function push() { - safe_ids = Object.create(safe_ids); - } - - function pop() { - safe_ids = Object.getPrototypeOf(safe_ids); - } - - function reset_def(def) { - def.direct_access = false; - def.escaped = false; - if (def.scope.uses_eval || def.scope.uses_with) { - def.fixed = false; - } else if (!compressor.exposed(def)) { - def.fixed = undefined; - } else { - def.fixed = false; + if (def.fixed != null && (!value || def.references.length > def.assignments)) return false; + if (def.fixed instanceof AST_Defun) { + return value instanceof AST_Node && def.fixed.parent_scope === scope; } - def.references = []; - def.should_replace = undefined; - def.single_use = undefined; + return all(def.orig, function(sym) { + return !(sym instanceof AST_SymbolDefun || sym instanceof AST_SymbolLambda); + }); } - function ref_once(def) { - return unused - && !def.scope.uses_eval - && !def.scope.uses_with - && def.references.length == 1 - && loop_ids[def.id] === in_loop; + function ref_once(tw, compressor, def) { + return compressor.option("unused") + && !def.scope.pinned() + && def.references.length - def.recursive_refs == 1 + && tw.loop_ids[def.id] === tw.in_loop; } function is_immutable(value) { @@ -606,70 +468,372 @@ merge(Compressor.prototype, { || value instanceof AST_This; } - function read_property(obj, key) { - if (key instanceof AST_Constant) key = key.getValue(); - if (key instanceof AST_Node) return null; - var value; - if (obj instanceof AST_Array) { - var elements = obj.elements; - if (key == "length") return make_node_from_constant(elements.length, obj); - if (typeof key == "number" && key in elements) value = elements[key]; - } else if (obj instanceof AST_Object) { - var props = obj.properties; - for (var i = props.length; --i >= 0;) { - var prop = props[i]; - if (!(prop instanceof AST_ObjectKeyVal)) return; - if (!value && props[i].key === key) value = props[i].value; - } - } - return value instanceof AST_SymbolRef && value.fixed_value() || value; - } - - function is_modified(node, value, level, immutable) { + function mark_escaped(tw, d, scope, node, value, level, depth) { var parent = tw.parent(level); - if (is_lhs(node, parent) - || !immutable - && parent instanceof AST_Call - && parent.expression === node - && (!(value instanceof AST_Function) - || !(parent instanceof AST_New) && value.contains_this())) { - return true; - } else if (parent instanceof AST_Array) { - return is_modified(parent, parent, level + 1); - } else if (parent instanceof AST_ObjectKeyVal && node === parent.value) { - var obj = tw.parent(level + 1); - return is_modified(obj, obj, level + 2); - } else if (parent instanceof AST_PropAccess && parent.expression === node) { - return !immutable && is_modified(parent, read_property(value, parent.property), level + 1); - } - } - - function mark_escaped(d, scope, node, value, level) { - var parent = tw.parent(level); - if (value) { - if (value.is_constant()) return; - if (level > 0 && value.is_constant_expression(scope)) return; - } + if (value && value.is_constant()) return; if (parent instanceof AST_Assign && parent.operator == "=" && node === parent.right - || parent instanceof AST_Call && node !== parent.expression + || parent instanceof AST_Call && (node !== parent.expression || parent instanceof AST_New) || parent instanceof AST_Exit && node === parent.value && node.scope !== d.scope || parent instanceof AST_VarDef && node === parent.value) { - d.escaped = true; + if (depth > 1 && !(value && value.is_constant_expression(scope))) depth = 1; + if (!d.escaped || d.escaped > depth) d.escaped = depth; return; } else if (parent instanceof AST_Array + || parent instanceof AST_Binary && lazy_op[parent.operator] || parent instanceof AST_Conditional && node !== parent.condition || parent instanceof AST_Sequence && node === parent.tail_node()) { - mark_escaped(d, scope, parent, parent, level + 1); + mark_escaped(tw, d, scope, parent, parent, level + 1, depth); } else if (parent instanceof AST_ObjectKeyVal && node === parent.value) { var obj = tw.parent(level + 1); - mark_escaped(d, scope, obj, obj, level + 2); + mark_escaped(tw, d, scope, obj, obj, level + 2, depth); } else if (parent instanceof AST_PropAccess && node === parent.expression) { value = read_property(value, parent.property); - mark_escaped(d, scope, parent, value, level + 1); + mark_escaped(tw, d, scope, parent, value, level + 1, depth + 1); if (value) return; } - if (level == 0) d.direct_access = true; + if (level > 0) return; + if (parent instanceof AST_Sequence && node !== parent.tail_node()) return; + if (parent instanceof AST_SimpleStatement) return; + d.direct_access = true; } + + var suppressor = new TreeWalker(function(node) { + if (!(node instanceof AST_Symbol)) return; + var d = node.definition(); + if (!d) return; + if (node instanceof AST_SymbolRef) d.references.push(node); + d.fixed = false; + }); + def(AST_Accessor, function(tw, descend, compressor) { + push(tw); + reset_variables(tw, compressor, this); + descend(); + pop(tw); + walk_defuns(tw, this); + return true; + }); + def(AST_Assign, function(tw, descend, compressor) { + var node = this; + var sym = node.left; + if (!(sym instanceof AST_SymbolRef)) return; + var d = sym.definition(); + var safe = safe_to_assign(tw, d, sym.scope, node.right); + d.assignments++; + if (!safe) return; + var fixed = d.fixed; + if (!fixed && node.operator != "=") return; + var eq = node.operator == "="; + var value = eq ? node.right : node; + if (is_modified(compressor, tw, node, value, 0)) return; + d.references.push(sym); + if (!eq) d.chained = true; + d.fixed = eq ? function() { + return node.right; + } : function() { + return make_node(AST_Binary, node, { + operator: node.operator.slice(0, -1), + left: fixed instanceof AST_Node ? fixed : fixed(), + right: node.right + }); + }; + mark(tw, d, false); + node.right.walk(tw); + mark(tw, d, true); + mark_escaped(tw, d, sym.scope, node, value, 0, 1); + return true; + }); + def(AST_Binary, function(tw) { + if (!lazy_op[this.operator]) return; + this.left.walk(tw); + push(tw); + this.right.walk(tw); + pop(tw); + return true; + }); + def(AST_Call, function(tw, descend) { + tw.find_parent(AST_Scope).may_call_this(); + var exp = this.expression; + if (!(exp instanceof AST_SymbolRef)) return; + var def = exp.definition(); + if (!(def.fixed instanceof AST_Defun)) return; + var defun = mark_defun(tw, def); + if (!defun) return; + descend(); + defun.walk(tw); + return true; + }); + def(AST_Case, function(tw) { + push(tw); + this.expression.walk(tw); + pop(tw); + push(tw); + walk_body(this, tw); + pop(tw); + return true; + }); + def(AST_Conditional, function(tw) { + this.condition.walk(tw); + push(tw); + this.consequent.walk(tw); + pop(tw); + push(tw); + this.alternative.walk(tw); + pop(tw); + return true; + }); + def(AST_Default, function(tw, descend) { + push(tw); + descend(); + pop(tw); + return true; + }); + def(AST_Defun, function(tw, descend, compressor) { + var id = this.name.definition().id; + if (tw.defun_visited[id]) return true; + if (tw.defun_ids[id] !== tw.safe_ids) return true; + tw.defun_visited[id] = true; + this.inlined = false; + push(tw); + reset_variables(tw, compressor, this); + descend(); + pop(tw); + walk_defuns(tw, this); + return true; + }); + def(AST_Do, function(tw) { + var saved_loop = tw.in_loop; + tw.in_loop = this; + push(tw); + this.body.walk(tw); + if (has_break_or_continue(this)) { + pop(tw); + push(tw); + } + this.condition.walk(tw); + pop(tw); + tw.in_loop = saved_loop; + return true; + }); + def(AST_For, function(tw) { + if (this.init) this.init.walk(tw); + var saved_loop = tw.in_loop; + tw.in_loop = this; + push(tw); + if (this.condition) this.condition.walk(tw); + this.body.walk(tw); + if (this.step) { + if (has_break_or_continue(this)) { + pop(tw); + push(tw); + } + this.step.walk(tw); + } + pop(tw); + tw.in_loop = saved_loop; + return true; + }); + def(AST_ForIn, function(tw) { + this.init.walk(suppressor); + this.object.walk(tw); + var saved_loop = tw.in_loop; + tw.in_loop = this; + push(tw); + this.body.walk(tw); + pop(tw); + tw.in_loop = saved_loop; + return true; + }); + def(AST_Function, function(tw, descend, compressor) { + var node = this; + node.inlined = false; + push(tw); + reset_variables(tw, compressor, node); + var iife; + if (!node.name + && (iife = tw.parent()) instanceof AST_Call + && iife.expression === node) { + // Virtually turn IIFE parameters into variable definitions: + // (function(a,b) {...})(c,d) => (function() {var a=c,b=d; ...})() + // So existing transformation rules can work on them. + node.argnames.forEach(function(arg, i) { + var d = arg.definition(); + if (d.fixed === undefined && (!node.uses_arguments || tw.has_directive("use strict"))) { + d.fixed = function() { + return iife.args[i] || make_node(AST_Undefined, iife); + }; + tw.loop_ids[d.id] = tw.in_loop; + mark(tw, d, true); + } else { + d.fixed = false; + } + }); + } + descend(); + pop(tw); + walk_defuns(tw, node); + return true; + }); + def(AST_If, function(tw) { + this.condition.walk(tw); + push(tw); + this.body.walk(tw); + pop(tw); + if (this.alternative) { + push(tw); + this.alternative.walk(tw); + pop(tw); + } + return true; + }); + def(AST_LabeledStatement, function(tw) { + push(tw); + this.body.walk(tw); + pop(tw); + return true; + }); + def(AST_SymbolCatch, function() { + this.definition().fixed = false; + }); + def(AST_SymbolRef, function(tw, descend, compressor) { + var d = this.definition(); + d.references.push(this); + if (d.references.length == 1 + && !d.fixed + && d.orig[0] instanceof AST_SymbolDefun) { + tw.loop_ids[d.id] = tw.in_loop; + } + var value; + if (d.fixed === undefined || !safe_to_read(tw, d)) { + d.fixed = false; + } else if (d.fixed) { + value = this.fixed_value(); + if (value instanceof AST_Lambda && recursive_ref(tw, d)) { + d.recursive_refs++; + } else if (value && ref_once(tw, compressor, d)) { + d.single_use = value instanceof AST_Lambda && !value.pinned() + || d.scope === this.scope && value.is_constant_expression(); + } else { + d.single_use = false; + } + if (is_modified(compressor, tw, this, value, 0, is_immutable(value))) { + if (d.single_use) { + d.single_use = "m"; + } else { + d.fixed = false; + } + } + } + mark_escaped(tw, d, this.scope, this, value, 0, 1); + var parent; + if (d.fixed instanceof AST_Defun + && !((parent = tw.parent()) instanceof AST_Call && parent.expression === this)) { + var defun = mark_defun(tw, d); + if (defun) defun.walk(tw); + } + }); + def(AST_Toplevel, function(tw, descend, compressor) { + this.globals.each(function(def) { + reset_def(tw, compressor, def); + }); + push(tw); + reset_variables(tw, compressor, this); + descend(); + pop(tw); + walk_defuns(tw, this); + return true; + }); + def(AST_Try, function(tw) { + push(tw); + walk_body(this, tw); + pop(tw); + if (this.bcatch) { + push(tw); + this.bcatch.walk(tw); + pop(tw); + } + if (this.bfinally) this.bfinally.walk(tw); + return true; + }); + def(AST_Unary, function(tw, descend) { + var node = this; + if (node.operator != "++" && node.operator != "--") return; + var exp = node.expression; + if (!(exp instanceof AST_SymbolRef)) return; + var d = exp.definition(); + var safe = safe_to_assign(tw, d, exp.scope, true); + d.assignments++; + if (!safe) return; + var fixed = d.fixed; + if (!fixed) return; + d.references.push(exp); + d.chained = true; + d.fixed = function() { + return make_node(AST_Binary, node, { + operator: node.operator.slice(0, -1), + left: make_node(AST_UnaryPrefix, node, { + operator: "+", + expression: fixed instanceof AST_Node ? fixed : fixed() + }), + right: make_node(AST_Number, node, { + value: 1 + }) + }); + }; + mark(tw, d, true); + return true; + }); + def(AST_VarDef, function(tw, descend) { + var node = this; + var d = node.name.definition(); + if (node.value) { + if (safe_to_assign(tw, d, node.name.scope, node.value)) { + d.fixed = function() { + return node.value; + }; + tw.loop_ids[d.id] = tw.in_loop; + mark(tw, d, false); + descend(); + mark(tw, d, true); + return true; + } else { + d.fixed = false; + } + } + }); + def(AST_While, function(tw, descend) { + var saved_loop = tw.in_loop; + tw.in_loop = this; + push(tw); + descend(); + pop(tw); + tw.in_loop = saved_loop; + return true; + }); + })(function(node, func) { + node.DEFMETHOD("reduce_vars", func); + }); + + AST_Toplevel.DEFMETHOD("reset_opt_flags", function(compressor) { + var tw = new TreeWalker(compressor.option("reduce_vars") ? function(node, descend) { + node._squeezed = false; + node._optimized = false; + return node.reduce_vars(tw, descend, compressor); + } : function(node) { + node._squeezed = false; + node._optimized = false; + }); + // Flow control for visiting `AST_Defun`s + tw.defun_ids = Object.create(null); + tw.defun_visited = Object.create(null); + // Record the loop body in which `AST_SymbolDeclaration` is first encountered + tw.in_loop = null; + tw.loop_ids = Object.create(null); + // Stack of look-up tables to keep track of whether a `SymbolDef` has been + // properly assigned before use: + // - `push()` & `pop()` when visiting conditional branches + // - backup & restore via `save_ids` when visiting out-of-order sections + tw.safe_ids = Object.create(null); + this.walk(tw); }); AST_Symbol.DEFMETHOD("fixed_value", function() { @@ -693,8 +857,7 @@ merge(Compressor.prototype, { lhs = lhs.fixed_value(); } if (!lhs) return true; - if (lhs instanceof AST_RegExp) return false; - if (lhs instanceof AST_Constant) return true; + if (lhs.is_constant()) return true; return is_lhs_read_only(lhs); } return false; @@ -719,7 +882,7 @@ merge(Compressor.prototype, { if (!props.end) props.end = orig.end; } return new ctor(props); - }; + } function make_sequence(orig, expressions) { if (expressions.length == 1) return expressions[0]; @@ -761,15 +924,21 @@ merge(Compressor.prototype, { type: typeof val })); } - }; + } + + function needs_unbinding(compressor, val) { + return val instanceof AST_PropAccess + || compressor.has_directive("use strict") + && is_undeclared_ref(val) + && val.name == "eval"; + } // we shouldn't compress (1,func)(something) to // func(something) because that changes the meaning of // the func (becomes lexical instead of global). - function maintain_this_binding(parent, orig, val) { + function maintain_this_binding(compressor, parent, orig, val) { if (parent instanceof AST_UnaryPrefix && parent.operator == "delete" - || parent instanceof AST_Call && parent.expression === orig - && (val instanceof AST_PropAccess || val instanceof AST_SymbolRef && val.name == "eval")) { + || parent.TYPE == "Call" && parent.expression === orig && needs_unbinding(compressor, val)) { return make_sequence(orig, [ make_node(AST_Number, orig, { value: 0 }), val ]); } return val; @@ -790,28 +959,30 @@ merge(Compressor.prototype, { if (thing instanceof AST_EmptyStatement) return []; if (thing instanceof AST_Statement) return [ thing ]; throw new Error("Can't convert thing to statement array"); - }; + } function is_empty(thing) { if (thing === null) return true; if (thing instanceof AST_EmptyStatement) return true; if (thing instanceof AST_BlockStatement) return thing.body.length == 0; return false; - }; + } function loop_body(x) { - if (x instanceof AST_Switch) return x; - if (x instanceof AST_For || x instanceof AST_ForIn || x instanceof AST_DWLoop) { - return (x.body instanceof AST_BlockStatement ? x.body : x); + if (x instanceof AST_IterationStatement) { + return x.body instanceof AST_BlockStatement ? x.body : x; } return x; - }; + } + + function root_expr(prop) { + while (prop instanceof AST_PropAccess) prop = prop.expression; + return prop; + } function is_iife_call(node) { - if (node instanceof AST_Call && !(node instanceof AST_New)) { - return node.expression instanceof AST_Function || is_iife_call(node.expression); - } - return false; + if (node.TYPE != "Call") return false; + return node.expression instanceof AST_Function || is_iife_call(node.expression); } function is_undeclared_ref(node) { @@ -821,9 +992,10 @@ merge(Compressor.prototype, { var global_names = makePredicate("Array Boolean clearInterval clearTimeout console Date decodeURI decodeURIComponent encodeURI encodeURIComponent Error escape eval EvalError Function isFinite isNaN JSON Math Number parseFloat parseInt RangeError ReferenceError RegExp Object setInterval setTimeout String SyntaxError TypeError unescape URIError"); AST_SymbolRef.DEFMETHOD("is_declared", function(compressor) { return !this.definition().undeclared - || compressor.option("unsafe") && global_names(this.name); + || compressor.option("unsafe") && global_names[this.name]; }); + var identifier_atom = makePredicate("Infinity NaN undefined"); function is_identifier_atom(node) { return node instanceof AST_Infinity || node instanceof AST_NaN @@ -831,6 +1003,8 @@ merge(Compressor.prototype, { } function tighten_body(statements, compressor) { + var in_loop, in_try, scope; + find_loop_scope_try(); var CHANGED, max_iter = 10; do { CHANGED = false; @@ -843,15 +1017,32 @@ merge(Compressor.prototype, { } if (compressor.sequences_limit > 0) { sequencesize(statements, compressor); + sequencesize_2(statements, compressor); } if (compressor.option("join_vars")) { - join_consecutive_vars(statements, compressor); + join_consecutive_vars(statements); } if (compressor.option("collapse_vars")) { collapse(statements, compressor); } } while (CHANGED && max_iter-- > 0); + function find_loop_scope_try() { + var node = compressor.self(), level = 0; + do { + if (node instanceof AST_Catch || node instanceof AST_Finally) { + level++; + } else if (node instanceof AST_IterationStatement) { + in_loop = true; + } else if (node instanceof AST_Scope) { + scope = node; + break; + } else if (node instanceof AST_Try) { + in_try = true; + } + } while (node = compressor.parent(level++)); + } + // Search from right to left for assignment-like expressions: // - `var a = x;` // - `a = x;` @@ -861,44 +1052,50 @@ merge(Compressor.prototype, { // Will not attempt to collapse assignments into or past code blocks // which are not sequentially executed, e.g. loops and conditionals. function collapse(statements, compressor) { - var scope = compressor.find_parent(AST_Scope); - if (scope.uses_eval || scope.uses_with) return statements; + if (scope.pinned()) return statements; var args; var candidates = []; var stat_index = statements.length; - var scanner = new TreeTransformer(function(node, descend) { + var scanner = new TreeTransformer(function(node) { if (abort) return node; // Skip nodes before `candidate` as quickly as possible if (!hit) { - if (node === candidate) { - hit = true; - return node; - } - return; + if (node !== hit_stack[hit_index]) return node; + hit_index++; + if (hit_index < hit_stack.length) return handle_custom_scan_order(node); + hit = true; + stop_after = find_stop(node, 0); + if (stop_after === node) abort = true; + return node; } // Stop immediately if these node types are encountered var parent = scanner.parent(); - if (node instanceof AST_Assign && node.operator != "=" && lhs.equivalent_to(node.left) - || node instanceof AST_Call && lhs instanceof AST_PropAccess && lhs.equivalent_to(node.expression) - || node instanceof AST_Debugger - || node instanceof AST_IterationStatement && !(node instanceof AST_For) - || node instanceof AST_SymbolRef && !node.is_declared(compressor) - || node instanceof AST_Try - || node instanceof AST_With - || parent instanceof AST_For && node !== parent.init) { + if (should_stop(node, parent)) { abort = true; return node; } + // Stop only if candidate is found within conditional branches + if (!stop_if_hit && in_conditional(node, parent)) { + stop_if_hit = parent; + } // Replace variable with assignment when found + var hit_lhs, hit_rhs; if (can_replace && !(node instanceof AST_SymbolDeclaration) - && lhs.equivalent_to(node)) { + && (scan_lhs && (hit_lhs = lhs.equivalent_to(node)) + || scan_rhs && (hit_rhs = scan_rhs(node, this)))) { + if (stop_if_hit && (hit_rhs || !lhs_local || !replace_all)) { + abort = true; + return node; + } if (is_lhs(node, parent)) { if (value_def) replaced++; return node; + } else { + replaced++; + if (value_def && candidate instanceof AST_VarDef) return node; } CHANGED = abort = true; - replaced++; compressor.info("Collapsing {name} [{file}:{line},{col}]", { name: node.print_to_string(), file: node.start.file, @@ -909,24 +1106,15 @@ merge(Compressor.prototype, { return make_node(AST_UnaryPrefix, candidate, candidate); } if (candidate instanceof AST_VarDef) { - if (value_def) { - abort = false; - return node; - } var def = candidate.name.definition(); - var value = candidate.value; if (def.references.length - def.replaced == 1 && !compressor.exposed(def)) { def.replaced++; - if (funarg && is_identifier_atom(value)) { - return value.transform(compressor); - } else { - return maintain_this_binding(parent, node, value); - } + return maintain_this_binding(compressor, parent, node, candidate.value); } return make_node(AST_Assign, candidate, { operator: "=", left: make_node(AST_SymbolRef, candidate.name, candidate.name), - right: value + right: candidate.value }); } candidate.write_only = false; @@ -935,36 +1123,25 @@ merge(Compressor.prototype, { // These node types have child nodes that execute sequentially, // but are otherwise not safe to scan into or beyond them. var sym; - if (node instanceof AST_Call - || node instanceof AST_Exit - || node instanceof AST_PropAccess - && (side_effects || node.expression.may_throw_on_access(compressor)) - || node instanceof AST_SymbolRef - && (lvalues[node.name] - || side_effects && !references_in_scope(node.definition())) - || (sym = lhs_or_def(node)) - && (sym instanceof AST_PropAccess || sym.name in lvalues) - || (side_effects || !replace_all) - && (parent instanceof AST_Binary && lazy_op(parent.operator) - || parent instanceof AST_Case - || parent instanceof AST_Conditional - || parent instanceof AST_If)) { - if (!(node instanceof AST_Scope)) descend(node, scanner); - abort = true; - return node; + if (is_last_node(node, parent) || may_throw(node)) { + stop_after = node; + if (node instanceof AST_Scope) abort = true; } - // Skip (non-executed) functions and (leading) default case in switch statements - if (node instanceof AST_Default || node instanceof AST_Scope) return node; + return handle_custom_scan_order(node); + }, function(node) { + if (abort) return; + if (stop_after === node) abort = true; + if (stop_if_hit === node) stop_if_hit = null; }); var multi_replacer = new TreeTransformer(function(node) { if (abort) return node; // Skip nodes before `candidate` as quickly as possible if (!hit) { - if (node === candidate) { - hit = true; - return node; - } - return; + if (node !== hit_stack[hit_index]) return node; + hit_index++; + if (hit_index < hit_stack.length) return; + hit = true; + return node; } // Replace variable when found if (node instanceof AST_SymbolRef @@ -973,7 +1150,7 @@ merge(Compressor.prototype, { if (is_lhs(node, multi_replacer.parent())) return node; def.replaced++; value_def.replaced--; - return candidate.value; + return candidate.value.clone(); } // Skip (non-executed) functions and (leading) default case in switch statements if (node instanceof AST_Default || node instanceof AST_Scope) return node; @@ -985,21 +1162,29 @@ merge(Compressor.prototype, { // var a = x(), b = undefined; if (stat_index == 0 && compressor.option("unused")) extract_args(); // Find collapsible assignments + var hit_stack = []; extract_candidates(statements[stat_index]); while (candidates.length > 0) { - var candidate = candidates.pop(); + hit_stack = candidates.pop(); + var hit_index = 0; + var candidate = hit_stack[hit_stack.length - 1]; var value_def = null; + var stop_after = null; + var stop_if_hit = null; var lhs = get_lhs(candidate); - if (!lhs || is_lhs_read_only(lhs) || lhs.has_side_effects(compressor)) continue; + var rhs = get_rhs(candidate); + var side_effects = lhs && lhs.has_side_effects(compressor); + var scan_lhs = lhs && !side_effects && !is_lhs_read_only(lhs); + var scan_rhs = rhs && foldable(rhs); + if (!scan_lhs && !scan_rhs) continue; // Locate symbols which may execute code outside of scanning range var lvalues = get_lvalues(candidate); - if (lhs instanceof AST_SymbolRef) lvalues[lhs.name] = false; - var replace_all = value_def; - if (!replace_all && lhs instanceof AST_SymbolRef) { - var def = lhs.definition(); - replace_all = def.references.length - def.replaced == 1; - } - var side_effects = value_has_side_effects(candidate); + var lhs_local = is_lhs_local(lhs); + if (!side_effects) side_effects = value_has_side_effects(candidate); + var replace_all = replace_all_symbols(); + var may_throw = candidate.may_throw(compressor) ? in_try ? function(node) { + return node.has_side_effects(compressor); + } : side_effects_external : return_false; var funarg = candidate.name instanceof AST_SymbolFunarg; var hit = funarg; var abort = false, replaced = 0, can_replace = !args || !hit; @@ -1017,22 +1202,96 @@ merge(Compressor.prototype, { if (abort && def.references.length - def.replaced > replaced) replaced = false; else { abort = false; + hit_index = 0; hit = funarg; for (var i = stat_index; !abort && i < statements.length; i++) { statements[i].transform(multi_replacer); } + value_def.single_use = false; } } if (replaced && !remove_candidate(candidate)) statements.splice(stat_index, 1); } } + function handle_custom_scan_order(node) { + // Skip (non-executed) functions + if (node instanceof AST_Scope) return node; + // Scan case expressions first in a switch statement + if (node instanceof AST_Switch) { + node.expression = node.expression.transform(scanner); + for (var i = 0, len = node.body.length; !abort && i < len; i++) { + var branch = node.body[i]; + if (branch instanceof AST_Case) { + if (!hit) { + if (branch !== hit_stack[hit_index]) continue; + hit_index++; + } + branch.expression = branch.expression.transform(scanner); + if (!replace_all) break; + } + } + abort = true; + return node; + } + } + + function should_stop(node, parent) { + if (parent instanceof AST_For) return node !== parent.init; + if (node instanceof AST_Assign) { + return node.operator != "=" && lhs.equivalent_to(node.left); + } + if (node instanceof AST_Call) { + return lhs instanceof AST_PropAccess && lhs.equivalent_to(node.expression); + } + if (node instanceof AST_Debugger) return true; + if (node instanceof AST_IterationStatement) return !(node instanceof AST_For); + if (node instanceof AST_LoopControl) return true; + if (node instanceof AST_Try) return true; + if (node instanceof AST_With) return true; + if (replace_all) return false; + return node instanceof AST_SymbolRef && !node.is_declared(compressor); + } + + function in_conditional(node, parent) { + if (parent instanceof AST_Binary) return lazy_op[parent.operator] && parent.left !== node; + if (parent instanceof AST_Conditional) return parent.condition !== node; + return parent instanceof AST_If && parent.condition !== node; + } + + function is_last_node(node, parent) { + if (node instanceof AST_Call) return true; + if (node instanceof AST_Exit) { + return side_effects || lhs instanceof AST_PropAccess || may_modify(lhs); + } + if (node instanceof AST_Function) { + return compressor.option("ie8") && node.name && node.name.name in lvalues; + } + if (node instanceof AST_PropAccess) { + return side_effects || node.expression.may_throw_on_access(compressor); + } + if (node instanceof AST_SymbolRef) { + if (symbol_in_lvalues(node, parent)) { + return !parent || parent.operator != "=" || parent.left !== node; + } + return side_effects && may_modify(node); + } + if (node instanceof AST_This) return symbol_in_lvalues(node, parent); + if (node instanceof AST_VarDef) { + if (!node.value) return false; + return node.name.name in lvalues || side_effects && may_modify(node.name); + } + var sym = is_lhs(node.left, node); + if (sym && sym.name in lvalues) return true; + if (sym instanceof AST_PropAccess) return true; + } + function extract_args() { var iife, fn = compressor.self(); if (fn instanceof AST_Function && !fn.name && !fn.uses_arguments - && !fn.uses_eval + && !fn.pinned() && (iife = compressor.parent()) instanceof AST_Call && iife.expression === fn) { var fn_strict = compressor.has_directive("use strict"); @@ -1049,9 +1308,12 @@ merge(Compressor.prototype, { })); if (sym.name in names) continue; names[sym.name] = true; - if (!arg) arg = make_node(AST_Undefined, sym).transform(compressor); - else { - var tw = new TreeWalker(function(node) { + if (!arg) { + arg = make_node(AST_Undefined, sym).transform(compressor); + } else if (arg instanceof AST_Lambda && arg.pinned()) { + arg = null; + } else { + arg.walk(new TreeWalker(function(node) { if (!arg) return true; if (node instanceof AST_SymbolRef && fn.variables.has(node.name)) { var s = node.definition().scope; @@ -1060,36 +1322,138 @@ merge(Compressor.prototype, { } arg = null; } - if (node instanceof AST_This && (fn_strict || !tw.find_parent(AST_Scope))) { + if (node instanceof AST_This && (fn_strict || !this.find_parent(AST_Scope))) { arg = null; return true; } - }); - arg.walk(tw); + })); } - if (arg) candidates.unshift(make_node(AST_VarDef, sym, { + if (arg) candidates.unshift([ make_node(AST_VarDef, sym, { name: sym, value: arg - })); + }) ]); } } } function extract_candidates(expr) { - if (expr instanceof AST_Assign && !expr.left.has_side_effects(compressor) - || expr instanceof AST_Unary && (expr.operator == "++" || expr.operator == "--")) { - candidates.push(expr); + hit_stack.push(expr); + if (expr instanceof AST_Assign) { + candidates.push(hit_stack.slice()); + extract_candidates(expr.right); + } else if (expr instanceof AST_Binary) { + extract_candidates(expr.left); + extract_candidates(expr.right); + } else if (expr instanceof AST_Call) { + extract_candidates(expr.expression); + expr.args.forEach(extract_candidates); + } else if (expr instanceof AST_Case) { + extract_candidates(expr.expression); + } else if (expr instanceof AST_Conditional) { + extract_candidates(expr.condition); + extract_candidates(expr.consequent); + extract_candidates(expr.alternative); + } else if (expr instanceof AST_Definitions) { + expr.definitions.forEach(extract_candidates); + } else if (expr instanceof AST_DWLoop) { + extract_candidates(expr.condition); + if (!(expr.body instanceof AST_Block)) { + extract_candidates(expr.body); + } + } else if (expr instanceof AST_Exit) { + if (expr.value) extract_candidates(expr.value); + } else if (expr instanceof AST_For) { + if (expr.init) extract_candidates(expr.init); + if (expr.condition) extract_candidates(expr.condition); + if (expr.step) extract_candidates(expr.step); + if (!(expr.body instanceof AST_Block)) { + extract_candidates(expr.body); + } + } else if (expr instanceof AST_ForIn) { + extract_candidates(expr.object); + if (!(expr.body instanceof AST_Block)) { + extract_candidates(expr.body); + } + } else if (expr instanceof AST_If) { + extract_candidates(expr.condition); + if (!(expr.body instanceof AST_Block)) { + extract_candidates(expr.body); + } + if (expr.alternative && !(expr.alternative instanceof AST_Block)) { + extract_candidates(expr.alternative); + } } else if (expr instanceof AST_Sequence) { expr.expressions.forEach(extract_candidates); - } else if (expr instanceof AST_Definitions) { - expr.definitions.forEach(function(var_def) { - if (var_def.value) candidates.push(var_def); - }); } else if (expr instanceof AST_SimpleStatement) { extract_candidates(expr.body); - } else if (expr instanceof AST_For && expr.init) { - extract_candidates(expr.init); + } else if (expr instanceof AST_Switch) { + extract_candidates(expr.expression); + expr.body.forEach(extract_candidates); + } else if (expr instanceof AST_Unary) { + if (expr.operator == "++" || expr.operator == "--") { + candidates.push(hit_stack.slice()); + } else { + extract_candidates(expr.expression); + } + } else if (expr instanceof AST_VarDef) { + if (expr.value) { + var def = expr.name.definition(); + if (def.references.length > def.replaced) { + candidates.push(hit_stack.slice()); + } + extract_candidates(expr.value); + } } + hit_stack.pop(); + } + + function find_stop(node, level, write_only) { + var parent = scanner.parent(level); + if (parent instanceof AST_Assign) { + if (write_only + && !(parent.left instanceof AST_PropAccess + || parent.left.name in lvalues)) { + return find_stop(parent, level + 1, write_only); + } + return node; + } + if (parent instanceof AST_Binary) { + if (write_only && (!lazy_op[parent.operator] || parent.left === node)) { + return find_stop(parent, level + 1, write_only); + } + return node; + } + if (parent instanceof AST_Call) return node; + if (parent instanceof AST_Case) return node; + if (parent instanceof AST_Conditional) { + if (write_only && parent.condition === node) { + return find_stop(parent, level + 1, write_only); + } + return node; + } + if (parent instanceof AST_Definitions) { + return find_stop(parent, level + 1, true); + } + if (parent instanceof AST_Exit) { + return write_only ? find_stop(parent, level + 1, write_only) : node; + } + if (parent instanceof AST_If) { + if (write_only && parent.condition === node) { + return find_stop(parent, level + 1, write_only); + } + return node; + } + if (parent instanceof AST_IterationStatement) return node; + if (parent instanceof AST_Sequence) { + return find_stop(parent, level + 1, parent.tail_node() !== node); + } + if (parent instanceof AST_SimpleStatement) { + return find_stop(parent, level + 1, true); + } + if (parent instanceof AST_Switch) return node; + if (parent instanceof AST_Unary) return node; + if (parent instanceof AST_VarDef) return node; + return null; } function mangleable_var(var_def) { @@ -1105,8 +1469,8 @@ merge(Compressor.prototype, { if (expr instanceof AST_VarDef) { var def = expr.name.definition(); if (!member(expr.name, def.orig)) return; - var declared = def.orig.length - def.eliminated; var referenced = def.references.length - def.replaced; + var declared = def.orig.length - def.eliminated; if (declared > 1 && !(expr.name instanceof AST_SymbolFunarg) || (referenced > 1 ? mangleable_var(expr) : !compressor.exposed(def))) { return make_node(AST_SymbolRef, expr.name, expr.name); @@ -1116,29 +1480,84 @@ merge(Compressor.prototype, { } } + function get_rhs(expr) { + return candidate instanceof AST_Assign && candidate.operator == "=" && candidate.right; + } + function get_rvalue(expr) { return expr[expr instanceof AST_Assign ? "right" : "value"]; } + function invariant(expr) { + if (expr instanceof AST_Array) return false; + if (expr instanceof AST_Binary && lazy_op[expr.operator]) { + return invariant(expr.left) && invariant(expr.right); + } + if (expr instanceof AST_Call) return false; + if (expr instanceof AST_Conditional) { + return invariant(expr.consequent) && invariant(expr.alternative); + } + if (expr instanceof AST_Object) return false; + return !expr.has_side_effects(compressor); + } + + function foldable(expr) { + if (expr instanceof AST_SymbolRef) { + var value = expr.evaluate(compressor); + if (value === expr) return rhs_exact_match; + return rhs_fuzzy_match(value, rhs_exact_match); + } + if (expr instanceof AST_This) return rhs_exact_match; + if (expr.is_truthy()) return rhs_fuzzy_match(true, return_false); + if (expr.is_constant()) { + return rhs_fuzzy_match(expr.evaluate(compressor), rhs_exact_match); + } + if (!(lhs instanceof AST_SymbolRef)) return false; + if (!invariant(expr)) return false; + var circular; + var def = lhs.definition(); + expr.walk(new TreeWalker(function(node) { + if (circular) return true; + if (node instanceof AST_SymbolRef && node.definition() === def) { + circular = true; + } + })); + return !circular && rhs_exact_match; + } + + function rhs_exact_match(node) { + return rhs.equivalent_to(node); + } + + function rhs_fuzzy_match(value, fallback) { + return function(node, tw) { + if (tw.in_boolean_context()) { + if (value && node.is_truthy() && !node.has_side_effects(compressor)) { + return true; + } + if (node.is_constant()) { + return !node.evaluate(compressor) == !value; + } + } + return fallback(node); + }; + } + function get_lvalues(expr) { var lvalues = Object.create(null); - if (expr instanceof AST_Unary) return lvalues; - var tw = new TreeWalker(function(node, descend) { - var sym = node; - while (sym instanceof AST_PropAccess) sym = sym.expression; + if (candidate instanceof AST_VarDef) { + lvalues[candidate.name.name] = lhs; + } + var tw = new TreeWalker(function(node) { + var sym = root_expr(node); if (sym instanceof AST_SymbolRef || sym instanceof AST_This) { - lvalues[sym.name] = lvalues[sym.name] || is_lhs(node, tw.parent()); + lvalues[sym.name] = lvalues[sym.name] || is_modified(compressor, tw, node, node, 0); } }); - get_rvalue(expr).walk(tw); + expr.walk(tw); return lvalues; } - function lhs_or_def(node) { - if (node instanceof AST_VarDef) return node.value && node.name; - return is_lhs(node.left, node); - } - function remove_candidate(expr) { if (expr.name instanceof AST_SymbolFunarg) { var index = compressor.self().argnames.indexOf(expr.name); @@ -1167,18 +1586,60 @@ merge(Compressor.prototype, { })); } + function is_lhs_local(lhs) { + var sym = root_expr(lhs); + return sym instanceof AST_SymbolRef + && sym.definition().scope === scope + && !(in_loop + && (sym.name in lvalues && lvalues[sym.name] !== lhs + || candidate instanceof AST_Unary + || candidate instanceof AST_Assign && candidate.operator != "=")); + } + function value_has_side_effects(expr) { if (expr instanceof AST_Unary) return false; return get_rvalue(expr).has_side_effects(compressor); } - function references_in_scope(def) { - if (def.orig.length == 1 && def.orig[0] instanceof AST_SymbolDefun) return true; - if (def.scope !== scope) return false; - return def.references.every(function(ref) { - return ref.scope === scope; + function replace_all_symbols() { + if (side_effects) return false; + if (value_def) return true; + if (lhs instanceof AST_SymbolRef) { + var def = lhs.definition(); + if (def.references.length - def.replaced == (candidate instanceof AST_VarDef ? 1 : 2)) { + return true; + } + } + return false; + } + + function symbol_in_lvalues(sym, parent) { + var lvalue = lvalues[sym.name]; + if (!lvalue) return; + if (lvalue !== lhs) return !(parent instanceof AST_Call); + scan_rhs = false; + } + + function may_modify(sym) { + var def = sym.definition(); + if (def.orig.length == 1 && def.orig[0] instanceof AST_SymbolDefun) return false; + if (def.scope !== scope) return true; + return !all(def.references, function(ref) { + return ref.scope.resolve() === scope; }); } + + function side_effects_external(node, lhs) { + if (node instanceof AST_Assign) return side_effects_external(node.left, true); + if (node instanceof AST_Unary) return side_effects_external(node.expression, true); + if (node instanceof AST_VarDef) return node.value && side_effects_external(node.value); + if (lhs) { + if (node instanceof AST_Dot) return side_effects_external(node.expression, true); + if (node instanceof AST_Sub) return side_effects_external(node.expression, true); + if (node instanceof AST_SymbolRef) return node.definition().scope !== scope; + } + return false; + } } function eliminate_spurious_blocks(statements) { @@ -1211,12 +1672,13 @@ merge(Compressor.prototype, { var in_lambda = self instanceof AST_Lambda; for (var i = statements.length; --i >= 0;) { var stat = statements[i]; - var next = statements[i + 1]; + var j = next_index(i); + var next = statements[j]; if (in_lambda && !next && stat instanceof AST_Return) { if (!stat.value) { CHANGED = true; - statements.length--; + statements.splice(i, 1); continue; } if (stat.value instanceof AST_UnaryPrefix && stat.value.operator == "void") { @@ -1248,6 +1710,19 @@ merge(Compressor.prototype, { continue; } + if (ab && !stat.alternative && stat.body instanceof AST_BlockStatement && next instanceof AST_Jump) { + var negated = stat.condition.negate(compressor); + if (negated.print_to_string().length <= stat.condition.print_to_string().length) { + CHANGED = true; + stat = stat.clone(); + stat.condition = negated; + statements[j] = stat.body; + stat.body = next; + statements[i] = stat.transform(compressor); + continue; + } + } + var ab = aborts(stat.alternative); if (can_merge_flow(ab)) { if (ab.label) { @@ -1286,19 +1761,22 @@ merge(Compressor.prototype, { CHANGED = true; stat = stat.clone(); stat.alternative = next; - statements.splice(i, 2, stat.transform(compressor)); + statements.splice(i, 1, stat.transform(compressor)); + statements.splice(j, 1); continue; } //--- // if (foo()) return x; [ return ; ] ==> return foo() ? x : undefined; - if (multiple_if_returns && in_lambda && value && !stat.alternative - && (!next || next instanceof AST_Return)) { + if (value && !stat.alternative + && (!next && in_lambda && multiple_if_returns + || next instanceof AST_Return)) { CHANGED = true; stat = stat.clone(); stat.alternative = next || make_node(AST_Return, stat, { value: null }); - statements.splice(i, next ? 2 : 1, stat.transform(compressor)); + statements.splice(i, 1, stat.transform(compressor)); + if (next) statements.splice(j, 1); continue; } //--- @@ -1307,10 +1785,10 @@ merge(Compressor.prototype, { // if sequences is not enabled, this can lead to an endless loop (issue #866). // however, with sequences on this helps producing slightly better output for // the example code. - var prev = statements[i - 1]; + var prev = statements[prev_index(i)]; if (compressor.option("sequences") && in_lambda && !stat.alternative && prev instanceof AST_If && prev.body instanceof AST_Return - && i + 2 == statements.length && next instanceof AST_SimpleStatement) { + && next_index(j) == statements.length && next instanceof AST_SimpleStatement) { CHANGED = true; stat = stat.clone(); stat.alternative = make_node(AST_BlockStatement, next, { @@ -1321,7 +1799,8 @@ merge(Compressor.prototype, { }) ] }); - statements.splice(i, 2, stat.transform(compressor)); + statements.splice(i, 1, stat.transform(compressor)); + statements.splice(j, 1); continue; } } @@ -1371,6 +1850,26 @@ merge(Compressor.prototype, { } return body; } + + function next_index(i) { + for (var j = i + 1, len = statements.length; j < len; j++) { + var stat = statements[j]; + if (!(stat instanceof AST_Var && declarations_only(stat))) { + break; + } + } + return j; + } + + function prev_index(i) { + for (var j = i; --j >= 0;) { + var stat = statements[j]; + if (!(stat instanceof AST_Var && declarations_only(stat))) { + break; + } + } + return j; + } } function eliminate_dead_code(statements, compressor) { @@ -1406,6 +1905,12 @@ merge(Compressor.prototype, { }); } + function declarations_only(node) { + return all(node.definitions, function(var_def) { + return !var_def.value; + }); + } + function sequencesize(statements, compressor) { if (statements.length < 2) return; var seq = [], n = 0; @@ -1422,6 +1927,9 @@ merge(Compressor.prototype, { var body = stat.body; if (seq.length > 0) body = body.drop_side_effect_free(compressor); if (body) merge_sequence(seq, body); + } else if (stat instanceof AST_Definitions && declarations_only(stat) + || stat instanceof AST_Defun) { + statements[n++] = stat; } else { push_seq(); statements[n++] = stat; @@ -1429,98 +1937,235 @@ merge(Compressor.prototype, { } push_seq(); statements.length = n; - sequencesize_2(statements, compressor); - CHANGED = statements.length != len; + if (n != len) CHANGED = true; + } + + function to_simple_statement(block, decls) { + if (!(block instanceof AST_BlockStatement)) return block; + var stat = null; + for (var i = 0, len = block.body.length; i < len; i++) { + var line = block.body[i]; + if (line instanceof AST_Var && declarations_only(line)) { + decls.push(line); + } else if (stat) { + return false; + } else { + stat = line; + } + } + return stat; } function sequencesize_2(statements, compressor) { function cons_seq(right) { n--; + CHANGED = true; var left = prev.body; return make_sequence(left, [ left, right ]).transform(compressor); - }; + } var n = 0, prev; - for (var i = 0, len = statements.length; i < len; i++) { + for (var i = 0; i < statements.length; i++) { var stat = statements[i]; if (prev) { - if (stat instanceof AST_For && !(stat.init instanceof AST_Definitions)) { - var abort = false; - prev.body.walk(new TreeWalker(function(node) { - if (abort || node instanceof AST_Scope) return true; - if (node instanceof AST_Binary && node.operator == "in") { - abort = true; - return true; - } - })); - if (!abort) { - if (stat.init) stat.init = cons_seq(stat.init); - else { - stat.init = prev.body; - n--; + if (stat instanceof AST_Exit) { + stat.value = cons_seq(stat.value || make_node(AST_Undefined, stat).transform(compressor)); + } else if (stat instanceof AST_For) { + if (!(stat.init instanceof AST_Definitions)) { + var abort = false; + prev.body.walk(new TreeWalker(function(node) { + if (abort || node instanceof AST_Scope) return true; + if (node instanceof AST_Binary && node.operator == "in") { + abort = true; + return true; + } + })); + if (!abort) { + if (stat.init) stat.init = cons_seq(stat.init); + else { + stat.init = prev.body; + n--; + CHANGED = true; + } } } - } - else if (stat instanceof AST_If) { + } else if (stat instanceof AST_ForIn) { + stat.object = cons_seq(stat.object); + } else if (stat instanceof AST_If) { stat.condition = cons_seq(stat.condition); - } - else if (stat instanceof AST_With) { + } else if (stat instanceof AST_Switch) { stat.expression = cons_seq(stat.expression); - } - else if (stat instanceof AST_Exit && stat.value) { - stat.value = cons_seq(stat.value); - } - else if (stat instanceof AST_Exit) { - stat.value = cons_seq(make_node(AST_Undefined, stat).transform(compressor)); - } - else if (stat instanceof AST_Switch) { + } else if (stat instanceof AST_With) { stat.expression = cons_seq(stat.expression); } } + if (compressor.option("conditionals") && stat instanceof AST_If) { + var decls = []; + var body = to_simple_statement(stat.body, decls); + var alt = to_simple_statement(stat.alternative, decls); + if (body !== false && alt !== false && decls.length > 0) { + var len = decls.length; + decls.push(make_node(AST_If, stat, { + condition: stat.condition, + body: body || make_node(AST_EmptyStatement, stat.body), + alternative: alt + })); + decls.unshift(n, 1); + [].splice.apply(statements, decls); + i += len; + n += len + 1; + prev = null; + CHANGED = true; + continue; + } + } statements[n++] = stat; prev = stat instanceof AST_SimpleStatement ? stat : null; } statements.length = n; } - function join_consecutive_vars(statements, compressor) { + function join_assigns(defn, body) { + var exprs; + if (body instanceof AST_Assign) { + exprs = [ body ]; + } else if (body instanceof AST_Sequence) { + exprs = body.expressions.slice(); + } + if (!exprs) return; + if (defn instanceof AST_Definitions) { + var def = defn.definitions[defn.definitions.length - 1]; + if (trim_assigns(def.name, def.value, exprs)) return exprs; + } + for (var i = exprs.length - 1; --i >= 0;) { + var expr = exprs[i]; + if (!(expr instanceof AST_Assign)) continue; + if (expr.operator != "=") continue; + if (!(expr.left instanceof AST_SymbolRef)) continue; + var tail = exprs.slice(i + 1); + if (!trim_assigns(expr.left, expr.right, tail)) continue; + return exprs.slice(0, i + 1).concat(tail); + } + } + + function trim_assigns(name, value, exprs) { + if (!(value instanceof AST_Object)) return; + var trimmed = false; + do { + var node = exprs[0]; + if (!(node instanceof AST_Assign)) break; + if (node.operator != "=") break; + if (!(node.left instanceof AST_PropAccess)) break; + var sym = node.left.expression; + if (!(sym instanceof AST_SymbolRef)) break; + if (name.name != sym.name) break; + if (!node.right.is_constant_expression(scope)) break; + var prop = node.left.property; + if (prop instanceof AST_Node) { + prop = prop.evaluate(compressor); + } + if (prop instanceof AST_Node) break; + prop = "" + prop; + var diff = compressor.has_directive("use strict") ? function(node) { + return node.key != prop && node.key.name != prop; + } : function(node) { + return node.key.name != prop; + }; + if (!all(value.properties, diff)) break; + value.properties.push(make_node(AST_ObjectKeyVal, node, { + key: prop, + value: node.right + })); + exprs.shift(); + trimmed = true; + } while (exprs.length); + return trimmed; + } + + function join_consecutive_vars(statements) { + var defs; for (var i = 0, j = -1, len = statements.length; i < len; i++) { var stat = statements[i]; var prev = statements[j]; - if (stat instanceof AST_Definitions && prev && prev.TYPE == stat.TYPE) { - prev.definitions = prev.definitions.concat(stat.definitions); - CHANGED = true; - } - else if (stat instanceof AST_For - && prev instanceof AST_Var - && (!stat.init || stat.init.TYPE == prev.TYPE)) { - CHANGED = true; - if (stat.init) { - stat.init.definitions = prev.definitions.concat(stat.init.definitions); + if (stat instanceof AST_Definitions) { + if (prev && prev.TYPE == stat.TYPE) { + prev.definitions = prev.definitions.concat(stat.definitions); + CHANGED = true; + } else if (defs && defs.TYPE == stat.TYPE && declarations_only(stat)) { + defs.definitions = defs.definitions.concat(stat.definitions); + CHANGED = true; } else { + statements[++j] = stat; + defs = stat; + } + } else if (stat instanceof AST_Exit) { + stat.value = join_assigns_expr(stat.value); + } else if (stat instanceof AST_For) { + var exprs = join_assigns(prev, stat.init); + if (exprs) { + CHANGED = true; + stat.init = exprs.length ? make_sequence(stat.init, exprs) : null; + statements[++j] = stat; + } else if (prev instanceof AST_Var && (!stat.init || stat.init.TYPE == prev.TYPE)) { + if (stat.init) { + prev.definitions = prev.definitions.concat(stat.init.definitions); + } stat.init = prev; + statements[j] = stat; + CHANGED = true; + } else if (defs && stat.init && defs.TYPE == stat.init.TYPE && declarations_only(stat.init)) { + defs.definitions = defs.definitions.concat(stat.init.definitions); + stat.init = null; + statements[++j] = stat; + CHANGED = true; + } else { + statements[++j] = stat; + } + } else if (stat instanceof AST_ForIn) { + stat.object = join_assigns_expr(stat.object); + } else if (stat instanceof AST_If) { + stat.condition = join_assigns_expr(stat.condition); + } else if (stat instanceof AST_SimpleStatement) { + var exprs = join_assigns(prev, stat.body); + if (exprs) { + CHANGED = true; + if (!exprs.length) continue; + stat.body = make_sequence(stat.body, exprs); } - statements[j] = stat; - } - else { + statements[++j] = stat; + } else if (stat instanceof AST_Switch) { + stat.expression = join_assigns_expr(stat.expression); + } else if (stat instanceof AST_With) { + stat.expression = join_assigns_expr(stat.expression); + } else { statements[++j] = stat; } } statements.length = j + 1; - }; + + function join_assigns_expr(value) { + statements[++j] = stat; + var exprs = join_assigns(prev, value); + if (!exprs) return value; + CHANGED = true; + var tail = value.tail_node(); + if (exprs[exprs.length - 1] !== tail) exprs.push(tail.left); + return make_sequence(value, exprs); + } + } } function extract_declarations_from_unreachable_code(compressor, stat, target) { if (!(stat instanceof AST_Defun)) { compressor.warn("Dropping unreachable code [{file}:{line},{col}]", stat.start); } - stat.walk(new TreeWalker(function(node){ + stat.walk(new TreeWalker(function(node) { if (node instanceof AST_Definitions) { compressor.warn("Declarations in unreachable code! [{file}:{line},{col}]", node.start); node.remove_initializers(); target.push(node); return true; } - if (node instanceof AST_Defun && (node === stat || !compressor.has_directive("use strict"))) { + if (node instanceof AST_Defun) { target.push(node); return true; } @@ -1528,7 +2173,19 @@ merge(Compressor.prototype, { return true; } })); - }; + } + + function get_value(key) { + if (key instanceof AST_Constant) { + return key.getValue(); + } + if (key instanceof AST_UnaryPrefix + && key.operator == "void" + && key.expression instanceof AST_Constant) { + return; + } + return key; + } function is_undefined(node, compressor) { return node.is_undefined @@ -1538,6 +2195,28 @@ merge(Compressor.prototype, { && !node.expression.has_side_effects(compressor); } + // is_truthy() + // return true if `!!node === true` + (function(def) { + def(AST_Node, return_false); + def(AST_Array, return_true); + def(AST_Assign, function() { + return this.operator == "=" && this.right.is_truthy(); + }); + def(AST_Lambda, return_true); + def(AST_Object, return_true); + def(AST_RegExp, return_true); + def(AST_Sequence, function() { + return this.tail_node().is_truthy(); + }); + def(AST_SymbolRef, function() { + var fixed = this.fixed_value(); + return fixed && fixed.is_truthy(); + }); + })(function(node, func) { + node.DEFMETHOD("is_truthy", func); + }); + // may_throw_on_access() // returns true if this node may be null, undefined or contain `AST_Accessor` (function(def) { @@ -1561,21 +2240,14 @@ merge(Compressor.prototype, { if (this.properties[i].value instanceof AST_Accessor) return true; return false; }); - def(AST_Function, return_false); + def(AST_Lambda, return_false); def(AST_UnaryPostfix, return_false); - def(AST_UnaryPrefix, function() { - return this.operator == "void"; - }); - def(AST_Binary, function(compressor) { - switch (this.operator) { - case "&&": - return this.left._dot_throw(compressor); - case "||": - return this.left._dot_throw(compressor) - && this.right._dot_throw(compressor); - default: - return false; - } + def(AST_UnaryPrefix, function() { + return this.operator == "void"; + }); + def(AST_Binary, function(compressor) { + return (this.operator == "&&" || this.operator == "||") + && (this.left._dot_throw(compressor) || this.right._dot_throw(compressor)); }) def(AST_Assign, function(compressor) { return this.operator == "=" @@ -1585,6 +2257,12 @@ merge(Compressor.prototype, { return this.consequent._dot_throw(compressor) || this.alternative._dot_throw(compressor); }) + def(AST_Dot, function(compressor) { + if (!is_strict(compressor)) return false; + var exp = this.expression; + if (exp instanceof AST_SymbolRef) exp = exp.fixed_value(); + return !(exp instanceof AST_Lambda && this.property == "prototype"); + }); def(AST_Sequence, function(compressor) { return this.tail_node()._dot_throw(compressor); }); @@ -1603,83 +2281,142 @@ merge(Compressor.prototype, { /* -----[ boolean/negation helpers ]----- */ // methods to determine whether an expression has a boolean result type - (function(def){ - var unary_bool = [ "!", "delete" ]; - var binary_bool = [ "in", "instanceof", "==", "!=", "===", "!==", "<", "<=", ">=", ">" ]; + (function(def) { def(AST_Node, return_false); - def(AST_UnaryPrefix, function(){ - return member(this.operator, unary_bool); + def(AST_Assign, function(compressor) { + return this.operator == "=" && this.right.is_boolean(compressor); + }); + var binary = makePredicate("in instanceof == != === !== < <= >= >"); + def(AST_Binary, function(compressor) { + return binary[this.operator] || lazy_op[this.operator] + && this.left.is_boolean(compressor) + && this.right.is_boolean(compressor); }); - def(AST_Binary, function(){ - return member(this.operator, binary_bool) - || lazy_op(this.operator) - && this.left.is_boolean() - && this.right.is_boolean(); + def(AST_Boolean, return_true); + var fn = makePredicate("every hasOwnProperty isPrototypeOf propertyIsEnumerable some"); + def(AST_Call, function(compressor) { + if (!compressor.option("unsafe")) return false; + var exp = this.expression; + return exp instanceof AST_Dot && (fn[exp.property] + || exp.property == "test" && exp.expression instanceof AST_RegExp); }); - def(AST_Conditional, function(){ - return this.consequent.is_boolean() && this.alternative.is_boolean(); + def(AST_Conditional, function(compressor) { + return this.consequent.is_boolean(compressor) && this.alternative.is_boolean(compressor); }); - def(AST_Assign, function(){ - return this.operator == "=" && this.right.is_boolean(); + def(AST_New, return_false); + def(AST_Sequence, function(compressor) { + return this.tail_node().is_boolean(compressor); }); - def(AST_Sequence, function(){ - return this.tail_node().is_boolean(); + var unary = makePredicate("! delete"); + def(AST_UnaryPrefix, function() { + return unary[this.operator]; }); - def(AST_True, return_true); - def(AST_False, return_true); - })(function(node, func){ + })(function(node, func) { node.DEFMETHOD("is_boolean", func); }); // methods to determine if an expression has a numeric result type - (function(def){ + (function(def) { def(AST_Node, return_false); - def(AST_Number, return_true); - var unary = makePredicate("+ - ~ ++ --"); - def(AST_Unary, function(){ - return unary(this.operator); - }); var binary = makePredicate("- * / % & | ^ << >> >>>"); - def(AST_Binary, function(compressor){ - return binary(this.operator) || this.operator == "+" + def(AST_Assign, function(compressor) { + return binary[this.operator.slice(0, -1)] + || this.operator == "=" && this.right.is_number(compressor); + }); + def(AST_Binary, function(compressor) { + return binary[this.operator] || this.operator == "+" && this.left.is_number(compressor) && this.right.is_number(compressor); }); - def(AST_Assign, function(compressor){ - return binary(this.operator.slice(0, -1)) - || this.operator == "=" && this.right.is_number(compressor); + var fn = makePredicate([ + "charCodeAt", + "getDate", + "getDay", + "getFullYear", + "getHours", + "getMilliseconds", + "getMinutes", + "getMonth", + "getSeconds", + "getTime", + "getTimezoneOffset", + "getUTCDate", + "getUTCDay", + "getUTCFullYear", + "getUTCHours", + "getUTCMilliseconds", + "getUTCMinutes", + "getUTCMonth", + "getUTCSeconds", + "getYear", + "indexOf", + "lastIndexOf", + "localeCompare", + "push", + "search", + "setDate", + "setFullYear", + "setHours", + "setMilliseconds", + "setMinutes", + "setMonth", + "setSeconds", + "setTime", + "setUTCDate", + "setUTCFullYear", + "setUTCHours", + "setUTCMilliseconds", + "setUTCMinutes", + "setUTCMonth", + "setUTCSeconds", + "setYear", + "toExponential", + "toFixed", + "toPrecision", + ]); + def(AST_Call, function(compressor) { + if (!compressor.option("unsafe")) return false; + var exp = this.expression; + return exp instanceof AST_Dot && (fn[exp.property] + || is_undeclared_ref(exp.expression) && exp.expression.name == "Math"); + }); + def(AST_Conditional, function(compressor) { + return this.consequent.is_number(compressor) && this.alternative.is_number(compressor); }); - def(AST_Sequence, function(compressor){ + def(AST_New, return_false); + def(AST_Number, return_true); + def(AST_Sequence, function(compressor) { return this.tail_node().is_number(compressor); }); - def(AST_Conditional, function(compressor){ - return this.consequent.is_number(compressor) && this.alternative.is_number(compressor); + var unary = makePredicate("+ - ~ ++ --"); + def(AST_Unary, function() { + return unary[this.operator]; }); - })(function(node, func){ + })(function(node, func) { node.DEFMETHOD("is_number", func); }); // methods to determine if an expression has a string result type - (function(def){ + (function(def) { def(AST_Node, return_false); def(AST_String, return_true); - def(AST_UnaryPrefix, function(){ + def(AST_UnaryPrefix, function() { return this.operator == "typeof"; }); - def(AST_Binary, function(compressor){ + def(AST_Binary, function(compressor) { return this.operator == "+" && (this.left.is_string(compressor) || this.right.is_string(compressor)); }); - def(AST_Assign, function(compressor){ + def(AST_Assign, function(compressor) { return (this.operator == "=" || this.operator == "+=") && this.right.is_string(compressor); }); - def(AST_Sequence, function(compressor){ + def(AST_Sequence, function(compressor) { return this.tail_node().is_string(compressor); }); - def(AST_Conditional, function(compressor){ + def(AST_Conditional, function(compressor) { return this.consequent.is_string(compressor) && this.alternative.is_string(compressor); }); - })(function(node, func){ + })(function(node, func) { node.DEFMETHOD("is_string", func); }); @@ -1687,27 +2424,11 @@ merge(Compressor.prototype, { var unary_side_effects = makePredicate("delete ++ --"); function is_lhs(node, parent) { - if (parent instanceof AST_Unary && unary_side_effects(parent.operator)) return parent.expression; + if (parent instanceof AST_Unary && unary_side_effects[parent.operator]) return parent.expression; if (parent instanceof AST_Assign && parent.left === node) return node; } - (function(def){ - AST_Node.DEFMETHOD("resolve_defines", function(compressor) { - if (!compressor.option("global_defs")) return; - var def = this._find_defs(compressor, ""); - if (def) { - var node, parent = this, level = 0; - do { - node = parent; - parent = compressor.parent(level++); - } while (parent instanceof AST_PropAccess && parent.expression === node); - if (is_lhs(node, parent)) { - compressor.warn('global_defs ' + this.print_to_string() + ' redefined [{file}:{line},{col}]', this.start); - } else { - return def; - } - } - }); + (function(def) { function to_node(value, orig) { if (value instanceof AST_Node) return make_node(value.CTOR, orig, value); if (Array.isArray(value)) return make_node(AST_Array, orig, { @@ -1729,27 +2450,45 @@ merge(Compressor.prototype, { } return make_node_from_constant(value, orig); } + + function warn(compressor, node) { + compressor.warn("global_defs " + node.print_to_string() + " redefined [{file}:{line},{col}]", node.start); + } + + AST_Toplevel.DEFMETHOD("resolve_defines", function(compressor) { + if (!compressor.option("global_defs")) return this; + this.figure_out_scope({ ie8: compressor.option("ie8") }); + return this.transform(new TreeTransformer(function(node) { + var def = node._find_defs(compressor, ""); + if (!def) return; + var level = 0, child = node, parent; + while (parent = this.parent(level++)) { + if (!(parent instanceof AST_PropAccess)) break; + if (parent.expression !== child) break; + child = parent; + } + if (is_lhs(child, parent)) { + warn(compressor, node); + return; + } + return def; + })); + }); def(AST_Node, noop); - def(AST_Dot, function(compressor, suffix){ + def(AST_Dot, function(compressor, suffix) { return this.expression._find_defs(compressor, "." + this.property + suffix); }); - def(AST_SymbolRef, function(compressor, suffix){ + def(AST_SymbolDeclaration, function(compressor) { + if (!this.global()) return; + if (HOP(compressor.option("global_defs"), this.name)) warn(compressor, this); + }); + def(AST_SymbolRef, function(compressor, suffix) { if (!this.global()) return; - var name; var defines = compressor.option("global_defs"); - if (defines && HOP(defines, (name = this.name + suffix))) { - var node = to_node(defines[name], this); - var top = compressor.find_parent(AST_Toplevel); - node.walk(new TreeWalker(function(node) { - if (node instanceof AST_SymbolRef) { - node.scope = top; - node.thedef = top.def_global(node); - } - })); - return node; - } + var name = this.name + suffix; + if (HOP(defines, name)) return to_node(defines[name], this); }); - })(function(node, func){ + })(function(node, func) { node.DEFMETHOD("_find_defs", func); }); @@ -1771,20 +2510,118 @@ merge(Compressor.prototype, { return (first_in_statement(compressor) ? best_of_statement : best_of_expression)(ast1, ast2); } + function convert_to_predicate(obj) { + for (var key in obj) { + obj[key] = makePredicate(obj[key]); + } + } + + var object_fns = [ + "constructor", + "toString", + "valueOf", + ]; + var native_fns = { + Array: [ + "indexOf", + "join", + "lastIndexOf", + "slice", + ].concat(object_fns), + Boolean: object_fns, + Function: object_fns, + Number: [ + "toExponential", + "toFixed", + "toPrecision", + ].concat(object_fns), + Object: object_fns, + RegExp: [ + "test", + ].concat(object_fns), + String: [ + "charAt", + "charCodeAt", + "concat", + "indexOf", + "italics", + "lastIndexOf", + "match", + "replace", + "search", + "slice", + "split", + "substr", + "substring", + "toLowerCase", + "toUpperCase", + "trim", + ].concat(object_fns), + }; + convert_to_predicate(native_fns); + var static_fns = { + Array: [ + "isArray", + ], + Math: [ + "abs", + "acos", + "asin", + "atan", + "ceil", + "cos", + "exp", + "floor", + "log", + "round", + "sin", + "sqrt", + "tan", + "atan2", + "pow", + "max", + "min", + ], + Number: [ + "isFinite", + "isNaN", + ], + Object: [ + "create", + "getOwnPropertyDescriptor", + "getOwnPropertyNames", + "getPrototypeOf", + "isExtensible", + "isFrozen", + "isSealed", + "keys", + ], + String: [ + "fromCharCode", + ], + }; + convert_to_predicate(static_fns); + // methods to evaluate a constant expression - (function(def){ + (function(def) { // If the node has been successfully reduced to a constant, // then its value is returned; otherwise the element itself // is returned. // They can be distinguished as constant value is never a // descendant of AST_Node. - AST_Node.DEFMETHOD("evaluate", function(compressor){ + AST_Node.DEFMETHOD("evaluate", function(compressor) { if (!compressor.option("evaluate")) return this; - var val = this._eval(compressor); - return !val || val instanceof RegExp || typeof val != "object" ? val : this; + var cached = []; + var val = this._eval(compressor, cached, 1); + cached.forEach(function(node) { + delete node._eval; + }); + if (!val || val instanceof RegExp) return val; + if (typeof val == "function" || typeof val == "object") return this; + return val; }); var unaryPrefix = makePredicate("! ~ - + void"); - AST_Node.DEFMETHOD("is_constant", function(){ + AST_Node.DEFMETHOD("is_constant", function() { // Accomodate when compress option evaluate=false // as well as the common constant expressions !0 and -1 if (this instanceof AST_Constant) { @@ -1792,29 +2629,34 @@ merge(Compressor.prototype, { } else { return this instanceof AST_UnaryPrefix && this.expression instanceof AST_Constant - && unaryPrefix(this.operator); + && unaryPrefix[this.operator]; } }); - def(AST_Statement, function(){ + def(AST_Statement, function() { throw new Error(string_template("Cannot evaluate a statement [{file}:{line},{col}]", this.start)); }); def(AST_Lambda, return_this); - function ev(node, compressor) { - if (!compressor) throw new Error("Compressor must be passed"); - - return node._eval(compressor); - }; def(AST_Node, return_this); - def(AST_Constant, function(){ + def(AST_Constant, function() { return this.getValue(); }); - def(AST_Array, function(compressor){ + def(AST_Function, function(compressor) { + if (compressor.option("unsafe")) { + var fn = function() {}; + fn.node = this; + fn.toString = function() { + return "function(){}"; + }; + return fn; + } + return this; + }); + def(AST_Array, function(compressor, cached, depth) { if (compressor.option("unsafe")) { var elements = []; for (var i = 0, len = this.elements.length; i < len; i++) { var element = this.elements[i]; - if (element instanceof AST_Function) continue; - var value = ev(element, compressor); + var value = element._eval(compressor, cached, depth); if (element === value) return this; elements.push(value); } @@ -1822,7 +2664,7 @@ merge(Compressor.prototype, { } return this; }); - def(AST_Object, function(compressor){ + def(AST_Object, function(compressor, cached, depth) { if (compressor.option("unsafe")) { var val = {}; for (var i = 0, len = this.properties.length; i < len; i++) { @@ -1831,21 +2673,22 @@ merge(Compressor.prototype, { if (key instanceof AST_Symbol) { key = key.name; } else if (key instanceof AST_Node) { - key = ev(key, compressor); + key = key._eval(compressor, cached, depth); if (key === prop.key) return this; } if (typeof Object.prototype[key] === 'function') { return this; } if (prop.value instanceof AST_Function) continue; - val[key] = ev(prop.value, compressor); + val[key] = prop.value._eval(compressor, cached, depth); if (val[key] === prop.value) return this; } return val; } return this; }); - def(AST_UnaryPrefix, function(compressor){ + var non_converting_unary = makePredicate("! typeof void"); + def(AST_UnaryPrefix, function(compressor, cached, depth) { var e = this.expression; // Function would be evaluated to an array and so typeof would // incorrectly return 'object'. Hence making is a special case. @@ -1856,7 +2699,8 @@ merge(Compressor.prototype, { && e.fixed_value() instanceof AST_Lambda)) { return typeof function(){}; } - e = ev(e, compressor); + if (!non_converting_unary[this.operator]) depth++; + e = e._eval(compressor, cached, depth); if (e === this.expression) return this; switch (this.operator) { case "!": return !e; @@ -1872,80 +2716,76 @@ merge(Compressor.prototype, { } return this; }); - def(AST_Binary, function(compressor){ - var left = ev(this.left, compressor); + var non_converting_binary = makePredicate("&& || === !=="); + def(AST_Binary, function(compressor, cached, depth) { + if (!non_converting_binary[this.operator]) depth++; + var left = this.left._eval(compressor, cached, depth); if (left === this.left) return this; - var right = ev(this.right, compressor); + var right = this.right._eval(compressor, cached, depth); if (right === this.right) return this; var result; switch (this.operator) { - case "&&" : result = left && right; break; - case "||" : result = left || right; break; - case "|" : result = left | right; break; - case "&" : result = left & right; break; - case "^" : result = left ^ right; break; - case "+" : result = left + right; break; - case "*" : result = left * right; break; - case "/" : result = left / right; break; - case "%" : result = left % right; break; - case "-" : result = left - right; break; - case "<<" : result = left << right; break; - case ">>" : result = left >> right; break; - case ">>>" : result = left >>> right; break; - case "==" : result = left == right; break; - case "===" : result = left === right; break; - case "!=" : result = left != right; break; - case "!==" : result = left !== right; break; - case "<" : result = left < right; break; - case "<=" : result = left <= right; break; - case ">" : result = left > right; break; - case ">=" : result = left >= right; break; - default: - return this; - } - if (isNaN(result) && compressor.find_parent(AST_With)) { - // leave original expression as is - return this; - } - return result; + case "&&" : result = left && right; break; + case "||" : result = left || right; break; + case "|" : result = left | right; break; + case "&" : result = left & right; break; + case "^" : result = left ^ right; break; + case "+" : result = left + right; break; + case "*" : result = left * right; break; + case "/" : result = left / right; break; + case "%" : result = left % right; break; + case "-" : result = left - right; break; + case "<<" : result = left << right; break; + case ">>" : result = left >> right; break; + case ">>>": result = left >>> right; break; + case "==" : result = left == right; break; + case "===": result = left === right; break; + case "!=" : result = left != right; break; + case "!==": result = left !== right; break; + case "<" : result = left < right; break; + case "<=" : result = left <= right; break; + case ">" : result = left > right; break; + case ">=" : result = left >= right; break; + default : return this; + } + return isNaN(result) && compressor.find_parent(AST_With) ? this : result; }); - def(AST_Conditional, function(compressor){ - var condition = ev(this.condition, compressor); + def(AST_Conditional, function(compressor, cached, depth) { + var condition = this.condition._eval(compressor, cached, depth); if (condition === this.condition) return this; var node = condition ? this.consequent : this.alternative; - var value = ev(node, compressor); + var value = node._eval(compressor, cached, depth); return value === node ? this : value; }); - def(AST_SymbolRef, function(compressor){ + def(AST_SymbolRef, function(compressor, cached, depth) { var fixed = this.fixed_value(); if (!fixed) return this; - this._eval = return_this; - var value = ev(fixed, compressor); - if (value === fixed) { + var value; + if (cached.indexOf(fixed) >= 0) { + value = fixed._eval(); + } else { + this._eval = return_this; + value = fixed._eval(compressor, cached, depth); delete this._eval; - return this; + if (value === fixed) return this; + fixed._eval = function() { + return value; + }; + cached.push(fixed); } - if (!HOP(fixed, "_eval")) fixed._eval = function() { - return value; - }; - if (value && typeof value == "object" && this.definition().escaped) { - delete this._eval; - return this; + if (value && typeof value == "object") { + var escaped = this.definition().escaped; + if (escaped && depth > escaped) return this; } - this._eval = fixed._eval; return value; }); var global_objs = { Array: Array, Math: Math, Number: Number, + Object: Object, String: String, }; - function convert_to_predicate(obj) { - for (var key in obj) { - obj[key] = makePredicate(obj[key]); - } - } var static_values = { Math: [ "E", @@ -1966,132 +2806,82 @@ merge(Compressor.prototype, { ], }; convert_to_predicate(static_values); - def(AST_PropAccess, function(compressor){ + def(AST_PropAccess, function(compressor, cached, depth) { if (compressor.option("unsafe")) { var key = this.property; if (key instanceof AST_Node) { - key = ev(key, compressor); + key = key._eval(compressor, cached, depth); if (key === this.property) return this; } var exp = this.expression; var val; if (is_undeclared_ref(exp)) { - if (!(static_values[exp.name] || return_false)(key)) return this; + var static_value = static_values[exp.name]; + if (!static_value || !static_value[key]) return this; val = global_objs[exp.name]; } else { - val = ev(exp, compressor); + val = exp._eval(compressor, cached, depth + 1); if (!val || val === exp || !HOP(val, key)) return this; + if (typeof val == "function") switch (key) { + case "name": + return val.node.name ? val.node.name.name : ""; + case "length": + return val.node.argnames.length; + default: + return this; + } } return val[key]; } return this; }); - var object_fns = [ - "constructor", - "toString", - "valueOf", - ]; - var native_fns = { - Array: [ - "indexOf", - "join", - "lastIndexOf", - "slice", - ].concat(object_fns), - Boolean: object_fns, - Number: [ - "toExponential", - "toFixed", - "toPrecision", - ].concat(object_fns), - RegExp: [ - "test", - ].concat(object_fns), - String: [ - "charAt", - "charCodeAt", - "concat", - "indexOf", - "italics", - "lastIndexOf", - "match", - "replace", - "search", - "slice", - "split", - "substr", - "substring", - "trim", - ].concat(object_fns), - }; - convert_to_predicate(native_fns); - var static_fns = { - Array: [ - "isArray", - ], - Math: [ - "abs", - "acos", - "asin", - "atan", - "ceil", - "cos", - "exp", - "floor", - "log", - "round", - "sin", - "sqrt", - "tan", - "atan2", - "pow", - "max", - "min" - ], - Number: [ - "isFinite", - "isNaN", - ], - String: [ - "fromCharCode", - ], - }; - convert_to_predicate(static_fns); - def(AST_Call, function(compressor){ + def(AST_Call, function(compressor, cached, depth) { var exp = this.expression; if (compressor.option("unsafe") && exp instanceof AST_PropAccess) { var key = exp.property; if (key instanceof AST_Node) { - key = ev(key, compressor); + key = key._eval(compressor, cached, depth); if (key === exp.property) return this; } var val; var e = exp.expression; if (is_undeclared_ref(e)) { - if (!(static_fns[e.name] || return_false)(key)) return this; + var static_fn = static_fns[e.name]; + if (!static_fn || !static_fn[key]) return this; val = global_objs[e.name]; } else { - val = ev(e, compressor); - if (val === e || !(val && native_fns[val.constructor.name] || return_false)(key)) return this; + val = e._eval(compressor, cached, depth + 1); + if (val === e || !val) return this; + var native_fn = native_fns[val.constructor.name]; + if (!native_fn || !native_fn[key]) return this; } var args = []; for (var i = 0, len = this.args.length; i < len; i++) { var arg = this.args[i]; - var value = ev(arg, compressor); + var value = arg._eval(compressor, cached, depth); if (arg === value) return this; args.push(value); } - return val[key].apply(val, args); + try { + return val[key].apply(val, args); + } catch (ex) { + compressor.warn("Error evaluating {code} [{file}:{line},{col}]", { + code: this.print_to_string(), + file: this.start.file, + line: this.start.line, + col: this.start.col + }); + } } return this; }); def(AST_New, return_this); - })(function(node, func){ + })(function(node, func) { node.DEFMETHOD("_eval", func); }); // method to negate an expression - (function(def){ + (function(def) { function basic_negation(exp) { return make_node(AST_UnaryPrefix, exp, { operator: "!", @@ -2108,32 +2898,32 @@ merge(Compressor.prototype, { } return best_of_expression(negated, alt); } - def(AST_Node, function(){ + def(AST_Node, function() { return basic_negation(this); }); - def(AST_Statement, function(){ + def(AST_Statement, function() { throw new Error("Cannot negate a statement"); }); - def(AST_Function, function(){ + def(AST_Function, function() { return basic_negation(this); }); - def(AST_UnaryPrefix, function(){ + def(AST_UnaryPrefix, function() { if (this.operator == "!") return this.expression; return basic_negation(this); }); - def(AST_Sequence, function(compressor){ + def(AST_Sequence, function(compressor) { var expressions = this.expressions.slice(); expressions.push(expressions.pop().negate(compressor)); return make_sequence(this, expressions); }); - def(AST_Conditional, function(compressor, first_in_statement){ + def(AST_Conditional, function(compressor, first_in_statement) { var self = this.clone(); self.consequent = self.consequent.negate(compressor); self.alternative = self.alternative.negate(compressor); return best(this, self, first_in_statement); }); - def(AST_Binary, function(compressor, first_in_statement){ + def(AST_Binary, function(compressor, first_in_statement) { var self = this.clone(), op = this.operator; if (compressor.option("unsafe_comps")) { switch (op) { @@ -2161,137 +2951,255 @@ merge(Compressor.prototype, { } return basic_negation(this); }); - })(function(node, func){ - node.DEFMETHOD("negate", function(compressor, first_in_statement){ + })(function(node, func) { + node.DEFMETHOD("negate", function(compressor, first_in_statement) { return func.call(this, compressor, first_in_statement); }); }); - AST_Call.DEFMETHOD("has_pure_annotation", function(compressor) { - if (!compressor.option("side_effects")) return false; - if (this.pure !== undefined) return this.pure; - var pure = false; - var comments, pure_comment; - if (this.start - && (comments = this.start.comments_before) - && comments.length - && (pure_comment = find_if(function (comment) { - return /[@#]__PURE__/.test(comment.value); - }, comments))) { - pure = pure_comment; - } - return this.pure = pure; - }); - var global_pure_fns = makePredicate("Boolean decodeURI decodeURIComponent Date encodeURI encodeURIComponent Error escape EvalError isFinite isNaN Number Object parseFloat parseInt RangeError ReferenceError String SyntaxError TypeError unescape URIError"); AST_Call.DEFMETHOD("is_expr_pure", function(compressor) { if (compressor.option("unsafe")) { var expr = this.expression; - if (is_undeclared_ref(expr) && global_pure_fns(expr.name)) return true; + if (is_undeclared_ref(expr) && global_pure_fns[expr.name]) return true; + if (expr instanceof AST_Dot && is_undeclared_ref(expr.expression)) { + var static_fn = static_fns[expr.expression.name]; + return static_fn && static_fn[expr.property]; + } } - return this.has_pure_annotation(compressor) || !compressor.pure_funcs(this); + return this.pure || !compressor.pure_funcs(this); + }); + AST_Node.DEFMETHOD("is_call_pure", return_false); + AST_Dot.DEFMETHOD("is_call_pure", function(compressor) { + if (!compressor.option("unsafe")) return; + var expr = this.expression; + var map; + if (expr instanceof AST_Array) { + map = native_fns.Array; + } else if (expr.is_boolean(compressor)) { + map = native_fns.Boolean; + } else if (expr.is_number(compressor)) { + map = native_fns.Number; + } else if (expr instanceof AST_RegExp) { + map = native_fns.RegExp; + } else if (expr.is_string(compressor)) { + map = native_fns.String; + } else if (!this.may_throw_on_access(compressor)) { + map = native_fns.Object; + } + return map && map[this.property]; }); // determine if expression has side effects - (function(def){ - def(AST_Node, return_true); - - def(AST_EmptyStatement, return_false); - def(AST_Constant, return_false); - def(AST_This, return_false); - - def(AST_Call, function(compressor){ - if (!this.is_expr_pure(compressor)) return true; - for (var i = this.args.length; --i >= 0;) { - if (this.args[i].has_side_effects(compressor)) - return true; - } - return false; - }); - + (function(def) { function any(list, compressor) { for (var i = list.length; --i >= 0;) if (list[i].has_side_effects(compressor)) return true; return false; } - - def(AST_Block, function(compressor){ + def(AST_Node, return_true); + def(AST_Array, function(compressor) { + return any(this.elements, compressor); + }); + def(AST_Assign, return_true); + def(AST_Binary, function(compressor) { + return this.left.has_side_effects(compressor) + || this.right.has_side_effects(compressor); + }); + def(AST_Block, function(compressor) { return any(this.body, compressor); }); - def(AST_Switch, function(compressor){ - return this.expression.has_side_effects(compressor) - || any(this.body, compressor); + def(AST_Call, function(compressor) { + if (!this.is_expr_pure(compressor) + && (!this.expression.is_call_pure(compressor) + || this.expression.has_side_effects(compressor))) { + return true; + } + return any(this.args, compressor); }); - def(AST_Case, function(compressor){ + def(AST_Case, function(compressor) { return this.expression.has_side_effects(compressor) || any(this.body, compressor); }); - def(AST_Try, function(compressor){ - return any(this.body, compressor) - || this.bcatch && this.bcatch.has_side_effects(compressor) - || this.bfinally && this.bfinally.has_side_effects(compressor); + 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_Constant, return_false); + def(AST_Definitions, function(compressor) { + return any(this.definitions, compressor); + }); + def(AST_Dot, function(compressor) { + return this.expression.may_throw_on_access(compressor) + || this.expression.has_side_effects(compressor); }); - def(AST_If, function(compressor){ + def(AST_EmptyStatement, return_false); + def(AST_If, function(compressor) { return this.condition.has_side_effects(compressor) || this.body && this.body.has_side_effects(compressor) || this.alternative && this.alternative.has_side_effects(compressor); }); - def(AST_LabeledStatement, function(compressor){ + def(AST_LabeledStatement, function(compressor) { return this.body.has_side_effects(compressor); }); - def(AST_SimpleStatement, function(compressor){ + def(AST_Lambda, return_false); + def(AST_Object, function(compressor) { + return any(this.properties, compressor); + }); + def(AST_ObjectProperty, function(compressor) { + return this.value.has_side_effects(compressor); + }); + def(AST_Sub, function(compressor) { + return this.expression.may_throw_on_access(compressor) + || this.expression.has_side_effects(compressor) + || this.property.has_side_effects(compressor); + }); + def(AST_Sequence, function(compressor) { + return any(this.expressions, compressor); + }); + def(AST_SimpleStatement, function(compressor) { return this.body.has_side_effects(compressor); }); - def(AST_Defun, return_true); - def(AST_Function, return_false); - def(AST_Binary, function(compressor){ - return this.left.has_side_effects(compressor) - || this.right.has_side_effects(compressor); + def(AST_Switch, function(compressor) { + return this.expression.has_side_effects(compressor) + || any(this.body, compressor); }); - def(AST_Assign, 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_SymbolDeclaration, return_false); + def(AST_SymbolRef, function(compressor) { + return !this.is_declared(compressor); + }); + def(AST_This, return_false); + def(AST_Try, function(compressor) { + return any(this.body, compressor) + || this.bcatch && this.bcatch.has_side_effects(compressor) + || this.bfinally && this.bfinally.has_side_effects(compressor); }); - def(AST_Unary, function(compressor){ - return unary_side_effects(this.operator) + def(AST_Unary, function(compressor) { + return unary_side_effects[this.operator] || this.expression.has_side_effects(compressor); }); - def(AST_SymbolRef, function(compressor){ - return !this.is_declared(compressor); + def(AST_VarDef, function(compressor) { + return this.value; }); + })(function(node, func) { + node.DEFMETHOD("has_side_effects", func); + }); + + // determine if expression may throw + (function(def) { + def(AST_Node, return_true); + + def(AST_Constant, return_false); + def(AST_EmptyStatement, return_false); + def(AST_Lambda, return_false); def(AST_SymbolDeclaration, return_false); - def(AST_Object, function(compressor){ - return any(this.properties, compressor); + def(AST_This, return_false); + + function any(list, compressor) { + for (var i = list.length; --i >= 0;) + if (list[i].may_throw(compressor)) + return true; + return false; + } + + def(AST_Array, function(compressor) { + return any(this.elements, compressor); }); - def(AST_ObjectProperty, function(compressor){ - return this.value.has_side_effects(compressor); + def(AST_Assign, function(compressor) { + if (this.right.may_throw(compressor)) return true; + if (!compressor.has_directive("use strict") + && this.operator == "=" + && this.left instanceof AST_SymbolRef) { + return false; + } + return this.left.may_throw(compressor); }); - def(AST_Array, function(compressor){ - return any(this.elements, compressor); + def(AST_Binary, function(compressor) { + return this.left.may_throw(compressor) + || this.right.may_throw(compressor); }); - def(AST_Dot, function(compressor){ + def(AST_Block, function(compressor) { + return any(this.body, compressor); + }); + def(AST_Call, function(compressor) { + if (any(this.args, compressor)) return true; + if (this.is_expr_pure(compressor)) return false; + if (this.expression.may_throw(compressor)) return true; + return !(this.expression instanceof AST_Lambda) + || any(this.expression.body, compressor); + }); + def(AST_Case, function(compressor) { + return this.expression.may_throw(compressor) + || any(this.body, compressor); + }); + def(AST_Conditional, function(compressor) { + return this.condition.may_throw(compressor) + || this.consequent.may_throw(compressor) + || this.alternative.may_throw(compressor); + }); + def(AST_Definitions, function(compressor) { + return any(this.definitions, compressor); + }); + def(AST_Dot, function(compressor) { return this.expression.may_throw_on_access(compressor) - || this.expression.has_side_effects(compressor); + || this.expression.may_throw(compressor); + }); + def(AST_If, function(compressor) { + return this.condition.may_throw(compressor) + || this.body && this.body.may_throw(compressor) + || this.alternative && this.alternative.may_throw(compressor); + }); + def(AST_LabeledStatement, function(compressor) { + return this.body.may_throw(compressor); + }); + def(AST_Object, function(compressor) { + return any(this.properties, compressor); + }); + def(AST_ObjectProperty, function(compressor) { + return this.value.may_throw(compressor); + }); + def(AST_Return, function(compressor) { + return this.value && this.value.may_throw(compressor); }); - def(AST_Sub, function(compressor){ + def(AST_Sequence, function(compressor) { + return any(this.expressions, compressor); + }); + def(AST_SimpleStatement, function(compressor) { + return this.body.may_throw(compressor); + }); + def(AST_Sub, function(compressor) { return this.expression.may_throw_on_access(compressor) - || this.expression.has_side_effects(compressor) - || this.property.has_side_effects(compressor); + || this.expression.may_throw(compressor) + || this.property.may_throw(compressor); }); - def(AST_Sequence, function(compressor){ - return this.expressions.some(function(expression, index) { - return expression.has_side_effects(compressor); - }); + def(AST_Switch, function(compressor) { + return this.expression.may_throw(compressor) + || any(this.body, compressor); }); - })(function(node, func){ - node.DEFMETHOD("has_side_effects", func); + def(AST_SymbolRef, function(compressor) { + return !this.is_declared(compressor); + }); + def(AST_Try, function(compressor) { + return this.bcatch ? this.bcatch.may_throw(compressor) : any(this.body, compressor) + || this.bfinally && this.bfinally.may_throw(compressor); + }); + def(AST_Unary, function(compressor) { + if (this.operator == "typeof" && this.expression instanceof AST_SymbolRef) + return false; + return this.expression.may_throw(compressor); + }); + def(AST_VarDef, function(compressor) { + if (!this.value) return false; + return this.value.may_throw(compressor); + }); + })(function(node, func) { + node.DEFMETHOD("may_throw", func); }); // determine if expression is constant - (function(def){ + (function(def) { function all(list) { for (var i = list.length; --i >= 0;) if (!list[i].is_constant_expression()) @@ -2300,7 +3208,7 @@ merge(Compressor.prototype, { } def(AST_Node, return_false); def(AST_Constant, return_true); - def(AST_Lambda, function(scope){ + def(AST_Lambda, function(scope) { var self = this; var result = true; self.walk(new TreeWalker(function(node) { @@ -2327,61 +3235,63 @@ merge(Compressor.prototype, { })); return result; }); - def(AST_Unary, function(){ + def(AST_Unary, function() { return this.expression.is_constant_expression(); }); - def(AST_Binary, function(){ + def(AST_Binary, function() { return this.left.is_constant_expression() && this.right.is_constant_expression(); }); - def(AST_Array, function(){ + def(AST_Array, function() { return all(this.elements); }); - def(AST_Object, function(){ + def(AST_Object, function() { return all(this.properties); }); - def(AST_ObjectProperty, function(){ + def(AST_ObjectProperty, function() { return this.value.is_constant_expression(); }); - })(function(node, func){ + })(function(node, func) { node.DEFMETHOD("is_constant_expression", func); }); // tell me if a statement aborts function aborts(thing) { return thing && thing.aborts(); - }; - (function(def){ + } + (function(def) { def(AST_Statement, return_null); def(AST_Jump, return_this); - function block_aborts(){ + function block_aborts() { var n = this.body.length; return n > 0 && aborts(this.body[n - 1]); - }; + } def(AST_BlockStatement, block_aborts); def(AST_SwitchBranch, block_aborts); - def(AST_If, function(){ + def(AST_If, function() { return this.alternative && aborts(this.body) && aborts(this.alternative) && this; }); - })(function(node, func){ + })(function(node, func) { node.DEFMETHOD("aborts", func); }); /* -----[ optimizers ]----- */ - OPT(AST_Directive, function(self, compressor){ - if (compressor.has_directive(self.value) !== self) { + var directives = makePredicate(["use asm", "use strict"]); + OPT(AST_Directive, function(self, compressor) { + if (compressor.option("directives") + && (!directives[self.value] || compressor.has_directive(self.value) !== self)) { return make_node(AST_EmptyStatement, self); } return self; }); - OPT(AST_Debugger, function(self, compressor){ + OPT(AST_Debugger, function(self, compressor) { if (compressor.option("drop_debugger")) return make_node(AST_EmptyStatement, self); return self; }); - OPT(AST_LabeledStatement, function(self, compressor){ + OPT(AST_LabeledStatement, function(self, compressor) { if (self.body instanceof AST_Break && compressor.loopcontrol_target(self.body) === self.body) { return make_node(AST_EmptyStatement, self); @@ -2389,35 +3299,58 @@ merge(Compressor.prototype, { return self.label.references.length == 0 ? self.body : self; }); - OPT(AST_Block, function(self, compressor){ + OPT(AST_Block, function(self, compressor) { tighten_body(self.body, compressor); return self; }); - OPT(AST_BlockStatement, function(self, compressor){ + OPT(AST_BlockStatement, function(self, compressor) { + tighten_body(self.body, compressor); + switch (self.body.length) { + case 1: return self.body[0]; + case 0: return make_node(AST_EmptyStatement, self); + } + return self; + }); + + OPT(AST_Lambda, function(self, compressor) { tighten_body(self.body, compressor); - switch (self.body.length) { - case 1: return self.body[0]; - case 0: return make_node(AST_EmptyStatement, self); + if (compressor.option("side_effects") + && self.body.length == 1 + && self.body[0] === compressor.has_directive("use strict")) { + self.body.length = 0; } return self; }); - AST_Scope.DEFMETHOD("drop_unused", function(compressor){ + AST_Scope.DEFMETHOD("drop_unused", function(compressor) { if (!compressor.option("unused")) return; if (compressor.has_directive("use asm")) return; var self = this; - if (self.uses_eval || self.uses_with) return; + if (self.pinned()) return; var drop_funcs = !(self instanceof AST_Toplevel) || compressor.toplevel.funcs; var drop_vars = !(self instanceof AST_Toplevel) || compressor.toplevel.vars; - var assign_as_unused = /keep_assign/.test(compressor.option("unused")) ? return_false : function(node) { + var assign_as_unused = /keep_assign/.test(compressor.option("unused")) ? return_false : function(node, props) { + var sym; if (node instanceof AST_Assign && (node.write_only || node.operator == "=")) { - return node.left; - } - if (node instanceof AST_Unary && node.write_only) return node.expression; + sym = node.left; + } else if (node instanceof AST_Unary && node.write_only) { + sym = node.expression; + } + if (!/strict/.test(compressor.option("pure_getters"))) return sym instanceof AST_SymbolRef && sym; + while (sym instanceof AST_PropAccess && !sym.expression.may_throw_on_access(compressor)) { + if (sym instanceof AST_Sub) props.unshift(sym.property); + sym = sym.expression; + } + return sym instanceof AST_SymbolRef && all(sym.definition().orig, function(sym) { + return !(sym instanceof AST_SymbolLambda); + }) && sym; }; var in_use = []; var in_use_ids = Object.create(null); // avoid expensive linear scans of in_use + var fixed_ids = Object.create(null); + var value_read = Object.create(null); + var value_modified = Object.create(null); if (self instanceof AST_Toplevel && compressor.top_retain) { self.variables.each(function(def) { if (compressor.top_retain(def) && !(def.id in in_use_ids)) { @@ -2431,24 +3364,33 @@ merge(Compressor.prototype, { // pass 1: find out which symbols are directly used in // this scope (not in nested scopes). var scope = this; - var tw = new TreeWalker(function(node, descend){ + var tw = new TreeWalker(function(node, descend) { + if (node instanceof AST_Lambda && node.uses_arguments && !tw.has_directive("use strict")) { + node.argnames.forEach(function(argname) { + var def = argname.definition(); + if (!(def.id in in_use_ids)) { + in_use_ids[def.id] = true; + in_use.push(def); + } + }); + } if (node === self) return; if (node instanceof AST_Defun) { + var node_def = node.name.definition(); if (!drop_funcs && scope === self) { - var node_def = node.name.definition(); if (!(node_def.id in in_use_ids)) { in_use_ids[node_def.id] = true; in_use.push(node_def); } } - initializations.add(node.name.name, node); + initializations.add(node_def.id, node); return true; // don't go in nested scopes } if (node instanceof AST_SymbolFunarg && scope === self) { var_defs_by_id.add(node.definition().id, node); } if (node instanceof AST_Definitions && scope === self) { - node.definitions.forEach(function(def){ + node.definitions.forEach(function(def) { var node_def = def.name.definition(); if (def.name instanceof AST_SymbolVar) { var_defs_by_id.add(node_def.id, def); @@ -2460,10 +3402,13 @@ merge(Compressor.prototype, { } } if (def.value) { - initializations.add(def.name.name, def.value); + initializations.add(node_def.id, def.value); if (def.value.has_side_effects(compressor)) { def.value.walk(tw); } + if (!node_def.chained && def.name.fixed_value() === def.value) { + fixed_ids[node_def.id] = def; + } } }); return true; @@ -2475,205 +3420,248 @@ merge(Compressor.prototype, { // initialization code to figure out if it uses other // symbols (that may not be in_use). tw = new TreeWalker(scan_ref_scoped); - for (var i = 0; i < in_use.length; ++i) { - in_use[i].orig.forEach(function(decl){ - // undeclared globals will be instanceof AST_SymbolRef - var init = initializations.get(decl.name); - if (init) init.forEach(function(init){ - init.walk(tw); - }); + for (var i = 0; i < in_use.length; i++) { + var init = initializations.get(in_use[i].id); + if (init) init.forEach(function(init) { + init.walk(tw); }); } + var drop_fn_name = compressor.option("keep_fnames") ? return_false : compressor.option("ie8") ? function(def) { + return !compressor.exposed(def) && !def.references.length; + } : function(def) { + // any declarations with same name will overshadow + // name of this anonymous function and can therefore + // never be used anywhere + return !(def.id in in_use_ids) || def.orig.length > 1; + }; // pass 3: we should drop declarations not in_use - var tt = new TreeTransformer( - function before(node, descend, in_list) { - var parent = tt.parent(); - if (drop_vars) { - var sym = assign_as_unused(node); - if (sym instanceof AST_SymbolRef - && !(sym.definition().id in in_use_ids)) { - if (node instanceof AST_Assign) { - return maintain_this_binding(parent, node, node.right.transform(tt)); + var tt = new TreeTransformer(function(node, descend, in_list) { + var parent = tt.parent(); + if (drop_vars) { + var props = [], sym = assign_as_unused(node, props); + if (sym) { + var def = sym.definition(); + var in_use = def.id in in_use_ids; + var value = null; + if (node instanceof AST_Assign) { + if (!in_use || node.left === sym && def.id in fixed_ids && fixed_ids[def.id] !== node) { + value = node.right; } - return make_node(AST_Number, node, { + } else if (!in_use) { + value = make_node(AST_Number, node, { value: 0 }); } + if (value) { + props.push(value); + return maintain_this_binding(compressor, parent, node, make_sequence(node, props.map(function(prop) { + return prop.transform(tt); + }))); + } } - if (scope !== self) return; - if (node instanceof AST_Function - && node.name - && !compressor.option("keep_fnames")) { - var def = node.name.definition(); - // any declarations with same name will overshadow - // name of this anonymous function and can therefore - // never be used anywhere - if (!(def.id in in_use_ids) || def.orig.length > 1) - node.name = null; - } - if (node instanceof AST_Lambda && !(node instanceof AST_Accessor)) { - var trim = !compressor.option("keep_fargs"); - for (var a = node.argnames, i = a.length; --i >= 0;) { - var sym = a[i]; - if (!(sym.definition().id in in_use_ids)) { - sym.__unused = true; - if (trim) { - a.pop(); - compressor[sym.unreferenced() ? "warn" : "info"]("Dropping unused function argument {name} [{file}:{line},{col}]", template(sym)); - } - } - else { - trim = false; + } + if (scope !== self) return; + if (node instanceof AST_Function && node.name && drop_fn_name(node.name.definition())) { + node.name = null; + } + if (node instanceof AST_Lambda && !(node instanceof AST_Accessor)) { + var trim = !compressor.option("keep_fargs"); + for (var a = node.argnames, i = a.length; --i >= 0;) { + var sym = a[i]; + if (!(sym.definition().id in in_use_ids)) { + sym.__unused = true; + if (trim) { + a.pop(); + compressor[sym.unreferenced() ? "warn" : "info"]("Dropping unused function argument {name} [{file}:{line},{col}]", template(sym)); } + } else { + trim = false; } } - if (drop_funcs && node instanceof AST_Defun && node !== self) { - var def = node.name.definition(); - if (!(def.id in in_use_ids)) { - compressor[node.name.unreferenced() ? "warn" : "info"]("Dropping unused function {name} [{file}:{line},{col}]", template(node.name)); - def.eliminated++; - return make_node(AST_EmptyStatement, node); - } + } + if (drop_funcs && node instanceof AST_Defun && node !== self) { + var def = node.name.definition(); + if (!(def.id in in_use_ids)) { + compressor[node.name.unreferenced() ? "warn" : "info"]("Dropping unused function {name} [{file}:{line},{col}]", template(node.name)); + def.eliminated++; + return make_node(AST_EmptyStatement, node); } - if (node instanceof AST_Definitions && !(parent instanceof AST_ForIn && parent.init === node)) { - // place uninitialized names at the start - var body = [], head = [], tail = []; - // for unused names whose initialization has - // side effects, we can cascade the init. code - // into the next one, or next statement. - var side_effects = []; - node.definitions.forEach(function(def) { - if (def.value) def.value = def.value.transform(tt); - var sym = def.name.definition(); - if (!drop_vars || sym.id in in_use_ids) { - if (def.name instanceof AST_SymbolVar) { - var var_defs = var_defs_by_id.get(sym.id); - if (var_defs.length > 1 && (!def.value || sym.orig.indexOf(def.name) > sym.eliminated)) { - compressor.warn("Dropping duplicated definition of variable {name} [{file}:{line},{col}]", template(def.name)); - if (def.value) { - side_effects.push(make_node(AST_Assign, def, { - operator: "=", - left: make_node(AST_SymbolRef, def.name, def.name), - right: def.value - })); + } + if (node instanceof AST_Definitions && !(parent instanceof AST_ForIn && parent.init === node)) { + // place uninitialized names at the start + var body = [], head = [], tail = []; + // for unused names whose initialization has + // side effects, we can cascade the init. code + // into the next one, or next statement. + var side_effects = []; + node.definitions.forEach(function(def) { + if (def.value) def.value = def.value.transform(tt); + var sym = def.name.definition(); + if (!drop_vars || sym.id in in_use_ids) { + if (def.value && sym.id in fixed_ids && fixed_ids[sym.id] !== def) { + def.value = def.value.drop_side_effect_free(compressor); + } + if (def.name instanceof AST_SymbolVar) { + var var_defs = var_defs_by_id.get(sym.id); + if (var_defs.length > 1 && (!def.value || sym.orig.indexOf(def.name) > sym.eliminated)) { + compressor.warn("Dropping duplicated definition of variable {name} [{file}:{line},{col}]", template(def.name)); + if (def.value) { + var ref = make_node(AST_SymbolRef, def.name, def.name); + sym.references.push(ref); + var assign = make_node(AST_Assign, def, { + operator: "=", + left: ref, + right: def.value + }); + if (fixed_ids[sym.id] === def) { + fixed_ids[sym.id] = assign; } - remove(var_defs, def); - sym.eliminated++; - return; + side_effects.push(assign.transform(tt)); } + remove(var_defs, def); + sym.eliminated++; + return; } - if (def.value) { - if (side_effects.length > 0) { - if (tail.length > 0) { - side_effects.push(def.value); - def.value = make_sequence(def.value, side_effects); - } else { - body.push(make_node(AST_SimpleStatement, node, { - body: make_sequence(node, side_effects) - })); - } - side_effects = []; + } + if (def.value) { + if (side_effects.length > 0) { + if (tail.length > 0) { + side_effects.push(def.value); + def.value = make_sequence(def.value, side_effects); + } else { + body.push(make_node(AST_SimpleStatement, node, { + body: make_sequence(node, side_effects) + })); } - tail.push(def); - } else { - head.push(def); + side_effects = []; } - } else if (sym.orig[0] instanceof AST_SymbolCatch) { - var value = def.value && def.value.drop_side_effect_free(compressor); - if (value) side_effects.push(value); - def.value = null; + tail.push(def); + } else { head.push(def); + } + } else if (sym.orig[0] instanceof AST_SymbolCatch) { + var value = def.value && def.value.drop_side_effect_free(compressor); + if (value) side_effects.push(value); + def.value = null; + head.push(def); + } else { + var value = def.value && def.value.drop_side_effect_free(compressor); + if (value) { + compressor.warn("Side effects in initialization of unused variable {name} [{file}:{line},{col}]", template(def.name)); + side_effects.push(value); } else { - var value = def.value && def.value.drop_side_effect_free(compressor); - if (value) { - compressor.warn("Side effects in initialization of unused variable {name} [{file}:{line},{col}]", template(def.name)); - side_effects.push(value); - } else { - compressor[def.name.unreferenced() ? "warn" : "info"]("Dropping unused variable {name} [{file}:{line},{col}]", template(def.name)); - } - sym.eliminated++; + compressor[def.name.unreferenced() ? "warn" : "info"]("Dropping unused variable {name} [{file}:{line},{col}]", template(def.name)); } - }); - if (head.length > 0 || tail.length > 0) { - node.definitions = head.concat(tail); - body.push(node); - } - if (side_effects.length > 0) { - body.push(make_node(AST_SimpleStatement, node, { - body: make_sequence(node, side_effects) - })); - } - switch (body.length) { - case 0: - return in_list ? MAP.skip : make_node(AST_EmptyStatement, node); - case 1: - return body[0]; - default: - return in_list ? MAP.splice(body) : make_node(AST_BlockStatement, node, { - body: body - }); + sym.eliminated++; } + }); + if (head.length > 0 || tail.length > 0) { + node.definitions = head.concat(tail); + body.push(node); } - // certain combination of unused name + side effect leads to: - // https://github.com/mishoo/UglifyJS2/issues/44 - // https://github.com/mishoo/UglifyJS2/issues/1830 - // https://github.com/mishoo/UglifyJS2/issues/1838 - // that's an invalid AST. - // We fix it at this stage by moving the `var` outside the `for`. - if (node instanceof AST_For) { - descend(node, this); - var block; - if (node.init instanceof AST_BlockStatement) { - block = node.init; - node.init = block.body.pop(); - block.body.push(node); - } - if (node.init instanceof AST_SimpleStatement) { - node.init = node.init.body; - } else if (is_empty(node.init)) { - node.init = null; - } - return !block ? node : in_list ? MAP.splice(block.body) : block; - } - if (node instanceof AST_LabeledStatement && node.body instanceof AST_For) { - descend(node, this); - if (node.body instanceof AST_BlockStatement) { - var block = node.body; - node.body = block.body.pop(); - block.body.push(node); - return in_list ? MAP.splice(block.body) : block; - } - return node; + if (side_effects.length > 0) { + body.push(make_node(AST_SimpleStatement, node, { + body: make_sequence(node, side_effects) + })); } - if (node instanceof AST_Scope) { - var save_scope = scope; - scope = node; - descend(node, this); - scope = save_scope; - return node; + switch (body.length) { + case 0: + return in_list ? MAP.skip : make_node(AST_EmptyStatement, node); + case 1: + return body[0]; + default: + return in_list ? MAP.splice(body) : make_node(AST_BlockStatement, node, { + body: body + }); } - - function template(sym) { - return { - name : sym.name, - file : sym.start.file, - line : sym.start.line, - col : sym.start.col - }; + } + // certain combination of unused name + side effect leads to: + // https://github.com/mishoo/UglifyJS2/issues/44 + // https://github.com/mishoo/UglifyJS2/issues/1830 + // https://github.com/mishoo/UglifyJS2/issues/1838 + // that's an invalid AST. + // We fix it at this stage by moving the `var` outside the `for`. + if (node instanceof AST_For) { + descend(node, this); + var block; + if (node.init instanceof AST_BlockStatement) { + block = node.init; + node.init = block.body.pop(); + block.body.push(node); + } + if (node.init instanceof AST_SimpleStatement) { + node.init = node.init.body; + } else if (is_empty(node.init)) { + node.init = null; } + return !block ? node : in_list ? MAP.splice(block.body) : block; + } + if (node instanceof AST_LabeledStatement && node.body instanceof AST_For) { + descend(node, this); + if (node.body instanceof AST_BlockStatement) { + var block = node.body; + node.body = block.body.pop(); + block.body.push(node); + return in_list ? MAP.splice(block.body) : block; + } + return node; + } + if (node instanceof AST_Scope) { + var save_scope = scope; + scope = node; + descend(node, this); + scope = save_scope; + return node; } - ); + + function template(sym) { + return { + name : sym.name, + file : sym.start.file, + line : sym.start.line, + col : sym.start.col + }; + } + }); self.transform(tt); + function verify_safe_usage(def, read, modified) { + if (def.id in in_use_ids) return; + if (read && modified) { + in_use_ids[def.id] = true; + in_use.push(def); + } else { + value_read[def.id] = read; + value_modified[def.id] = modified; + } + } + function scan_ref_scoped(node, descend) { - var sym; - if ((sym = assign_as_unused(node)) instanceof AST_SymbolRef - && self.variables.get(sym.name) === sym.definition()) { - if (node instanceof AST_Assign) node.right.walk(tw); + var node_def, props = [], sym = assign_as_unused(node, props); + if (sym && self.variables.get(sym.name) === (node_def = sym.definition())) { + props.forEach(function(prop) { + prop.walk(tw); + }); + if (node instanceof AST_Assign) { + node.right.walk(tw); + if (node.left === sym) { + if (!node_def.chained && sym.fixed_value() === node.right) { + fixed_ids[node_def.id] = node; + } + if (!node.write_only) { + verify_safe_usage(node_def, true, value_modified[node_def.id]); + } + } else { + var fixed = sym.fixed_value(); + if (!fixed || !fixed.is_constant()) { + verify_safe_usage(node_def, value_read[node_def.id], true); + } + } + } return true; } if (node instanceof AST_SymbolRef) { - var node_def = node.definition(); + node_def = node.definition(); if (!(node_def.id in in_use_ids)) { in_use_ids[node_def.id] = true; in_use.push(node_def); @@ -2690,140 +3678,134 @@ merge(Compressor.prototype, { } }); - AST_Scope.DEFMETHOD("hoist_declarations", function(compressor){ - var self = this; - if (compressor.has_directive("use asm")) return self; + AST_Scope.DEFMETHOD("hoist_declarations", function(compressor) { + if (compressor.has_directive("use asm")) return; var hoist_funs = compressor.option("hoist_funs"); var hoist_vars = compressor.option("hoist_vars"); - if (hoist_funs || hoist_vars) { - var dirs = []; - var hoisted = []; - var vars = new Dictionary(), vars_found = 0, var_decl = 0; + var self = this; + if (hoist_vars) { // let's count var_decl first, we seem to waste a lot of // space if we hoist `var` when there's only one. - self.walk(new TreeWalker(function(node){ - if (node instanceof AST_Scope && node !== self) - return true; + var var_decl = 0; + self.walk(new TreeWalker(function(node) { + if (var_decl > 1) return true; + if (node instanceof AST_Scope && node !== self) return true; if (node instanceof AST_Var) { - ++var_decl; + var_decl++; return true; } })); - hoist_vars = hoist_vars && var_decl > 1; - var tt = new TreeTransformer( - function before(node) { - if (node !== self) { - if (node instanceof AST_Directive) { - dirs.push(node); - return make_node(AST_EmptyStatement, node); - } - if (hoist_funs && node instanceof AST_Defun - && (tt.parent() === self || !compressor.has_directive("use strict"))) { - hoisted.push(node); - return make_node(AST_EmptyStatement, node); - } - if (hoist_vars && node instanceof AST_Var) { - node.definitions.forEach(function(def){ - vars.set(def.name.name, def); - ++vars_found; - }); - var seq = node.to_assignments(compressor); - var p = tt.parent(); - if (p instanceof AST_ForIn && p.init === node) { - if (seq == null) { - var def = node.definitions[0].name; - return make_node(AST_SymbolRef, def, def); - } - return seq; - } - if (p instanceof AST_For && p.init === node) { - return seq; - } - if (!seq) return make_node(AST_EmptyStatement, node); - return make_node(AST_SimpleStatement, node, { - body: seq - }); - } - if (node instanceof AST_Scope) - return node; // to avoid descending in nested scopes - } + if (var_decl <= 1) hoist_vars = false; + } + if (!hoist_funs && !hoist_vars) return; + var dirs = []; + var hoisted = []; + var vars = new Dictionary(), vars_found = 0; + var tt = new TreeTransformer(function(node) { + if (node === self) return; + if (node instanceof AST_Directive) { + dirs.push(node); + return make_node(AST_EmptyStatement, node); + } + if (hoist_funs && node instanceof AST_Defun + && (tt.parent() === self || !compressor.has_directive("use strict"))) { + hoisted.push(node); + return make_node(AST_EmptyStatement, node); + } + if (hoist_vars && node instanceof AST_Var) { + node.definitions.forEach(function(def) { + vars.set(def.name.name, def); + ++vars_found; + }); + var seq = node.to_assignments(compressor); + var p = tt.parent(); + if (p instanceof AST_ForIn && p.init === node) { + if (seq) return seq; + var def = node.definitions[0].name; + return make_node(AST_SymbolRef, def, def); } - ); - self = self.transform(tt); - if (vars_found > 0) { - // collect only vars which don't show up in self's arguments list - var defs = []; - vars.each(function(def, name){ - if (self instanceof AST_Lambda - && find_if(function(x){ return x.name == def.name.name }, - self.argnames)) { - vars.del(name); - } else { - def = def.clone(); - def.value = null; - defs.push(def); - vars.set(name, def); - } + if (p instanceof AST_For && p.init === node) return seq; + if (!seq) return make_node(AST_EmptyStatement, node); + return make_node(AST_SimpleStatement, node, { + body: seq }); - if (defs.length > 0) { - // try to merge in assignments - for (var i = 0; i < self.body.length;) { - if (self.body[i] instanceof AST_SimpleStatement) { - var expr = self.body[i].body, sym, assign; - if (expr instanceof AST_Assign - && expr.operator == "=" - && (sym = expr.left) instanceof AST_Symbol - && vars.has(sym.name)) - { - var def = vars.get(sym.name); - if (def.value) break; - def.value = expr.right; - remove(defs, def); - defs.push(def); - self.body.splice(i, 1); - continue; - } - if (expr instanceof AST_Sequence - && (assign = expr.expressions[0]) instanceof AST_Assign - && assign.operator == "=" - && (sym = assign.left) instanceof AST_Symbol - && vars.has(sym.name)) - { - var def = vars.get(sym.name); - if (def.value) break; - def.value = assign.right; - remove(defs, def); - defs.push(def); - self.body[i].body = make_sequence(expr, expr.expressions.slice(1)); - continue; - } - } - if (self.body[i] instanceof AST_EmptyStatement) { + } + if (node instanceof AST_Scope) return node; + }); + self.transform(tt); + if (vars_found > 0) { + // collect only vars which don't show up in self's arguments list + var defs = []; + vars.each(function(def, name) { + if (self instanceof AST_Lambda + && !all(self.argnames, function(argname) { + return argname.name != name; + })) { + vars.del(name); + } else { + def = def.clone(); + def.value = null; + defs.push(def); + vars.set(name, def); + } + }); + if (defs.length > 0) { + // try to merge in assignments + for (var i = 0; i < self.body.length;) { + if (self.body[i] instanceof AST_SimpleStatement) { + var expr = self.body[i].body, sym, assign; + if (expr instanceof AST_Assign + && expr.operator == "=" + && (sym = expr.left) instanceof AST_Symbol + && vars.has(sym.name)) + { + var def = vars.get(sym.name); + if (def.value) break; + def.value = expr.right; + remove(defs, def); + defs.push(def); self.body.splice(i, 1); continue; } - if (self.body[i] instanceof AST_BlockStatement) { - var tmp = [ i, 1 ].concat(self.body[i].body); - self.body.splice.apply(self.body, tmp); + if (expr instanceof AST_Sequence + && (assign = expr.expressions[0]) instanceof AST_Assign + && assign.operator == "=" + && (sym = assign.left) instanceof AST_Symbol + && vars.has(sym.name)) + { + var def = vars.get(sym.name); + if (def.value) break; + def.value = assign.right; + remove(defs, def); + defs.push(def); + self.body[i].body = make_sequence(expr, expr.expressions.slice(1)); continue; } - break; } - defs = make_node(AST_Var, self, { - definitions: defs - }); - hoisted.push(defs); - }; + if (self.body[i] instanceof AST_EmptyStatement) { + self.body.splice(i, 1); + continue; + } + if (self.body[i] instanceof AST_BlockStatement) { + var tmp = [ i, 1 ].concat(self.body[i].body); + self.body.splice.apply(self.body, tmp); + continue; + } + break; + } + defs = make_node(AST_Var, self, { + definitions: defs + }); + hoisted.push(defs); } - self.body = dirs.concat(hoisted, self.body); } - return self; + self.body = dirs.concat(hoisted, self.body); }); - AST_Scope.DEFMETHOD("make_var_name", function(prefix) { - var var_names = this.var_names; + AST_Scope.DEFMETHOD("var_names", function() { + var var_names = this._var_names; if (!var_names) { - this.var_names = var_names = Object.create(null); + this._var_names = var_names = Object.create(null); this.enclosed.forEach(function(def) { var_names[def.name] = true; }); @@ -2831,47 +3813,73 @@ merge(Compressor.prototype, { var_names[name] = true; }); } - prefix = prefix.replace(/[^a-z_$]+/ig, "_"); + return var_names; + }); + + AST_Scope.DEFMETHOD("make_var_name", function(prefix) { + var var_names = this.var_names(); + prefix = prefix.replace(/(?:^[^a-z_$]|[^a-z0-9_$])/ig, "_"); var name = prefix; for (var i = 0; var_names[name]; i++) name = prefix + "$" + i; var_names[name] = true; return name; }); - AST_Scope.DEFMETHOD("hoist_properties", function(compressor){ + AST_Scope.DEFMETHOD("hoist_properties", function(compressor) { + if (!compressor.option("hoist_props") || compressor.has_directive("use asm")) return; var self = this; - if (!compressor.option("hoist_props") || compressor.has_directive("use asm")) return self; var top_retain = self instanceof AST_Toplevel && compressor.top_retain || return_false; var defs_by_id = Object.create(null); - return self.transform(new TreeTransformer(function(node, descend) { - if (node instanceof AST_VarDef) { - var sym = node.name, def, value; - if (sym.scope === self - && !(def = sym.definition()).escaped - && !def.single_use - && !def.direct_access - && !top_retain(def) - && (value = sym.fixed_value()) === node.value - && value instanceof AST_Object) { - descend(node, this); - var defs = new Dictionary(); - var assignments = []; - value.properties.forEach(function(prop) { - assignments.push(make_node(AST_VarDef, node, { - name: make_sym(prop.key), - value: prop.value - })); + self.transform(new TreeTransformer(function(node, descend) { + if (node instanceof AST_Assign + && node.operator == "=" + && node.write_only + && can_hoist(node.left, node.right, 1)) { + descend(node, this); + var defs = new Dictionary(); + var assignments = []; + var decls = []; + node.right.properties.forEach(function(prop) { + var decl = make_sym(node.left, prop.key); + decls.push(make_node(AST_VarDef, node, { + name: decl, + value: null + })); + var sym = make_node(AST_SymbolRef, node, { + name: decl.name, + scope: self, + thedef: decl.definition() }); - defs_by_id[def.id] = defs; - return MAP.splice(assignments); - } + sym.reference({}); + assignments.push(make_node(AST_Assign, node, { + operator: "=", + left: sym, + right: prop.value + })); + }); + defs_by_id[node.left.definition().id] = defs; + self.body.splice(self.body.indexOf(this.stack[1]) + 1, 0, make_node(AST_Var, node, { + definitions: decls + })); + return make_sequence(node, assignments); + } + if (node instanceof AST_VarDef && can_hoist(node.name, node.value, 0)) { + descend(node, this); + var defs = new Dictionary(); + var var_defs = []; + node.value.properties.forEach(function(prop) { + var_defs.push(make_node(AST_VarDef, node, { + name: make_sym(node.name, prop.key), + value: prop.value + })); + }); + defs_by_id[node.name.definition().id] = defs; + return MAP.splice(var_defs); } if (node instanceof AST_PropAccess && node.expression instanceof AST_SymbolRef) { var defs = defs_by_id[node.expression.definition().id]; if (defs) { - var key = node.property; - if (key instanceof AST_Node) key = key.getValue(); - var def = defs.get(key); + var def = defs.get(get_value(node.property)); var sym = make_node(AST_SymbolRef, node, { name: def.name, scope: node.expression.scope, @@ -2882,8 +3890,21 @@ merge(Compressor.prototype, { } } - function make_sym(key) { - var new_var = make_node(sym.CTOR, sym, { + function can_hoist(sym, right, count) { + if (sym.scope !== self) return; + var def = sym.definition(); + if (def.assignments != count) return; + if (def.direct_access) return; + if (def.escaped == 1) return; + if (def.references.length == count) return; + if (def.single_use) return; + if (top_retain(def)) return; + if (sym.fixed_value() !== right) return; + return right instanceof AST_Object; + } + + function make_sym(sym, key) { + var new_var = make_node(AST_SymbolVar, sym, { name: self.make_var_name(sym.name + "_" + key), scope: self }); @@ -2897,7 +3918,7 @@ merge(Compressor.prototype, { // drop_side_effect_free() // remove side-effect-free parts which only affects return value - (function(def){ + (function(def) { // Drop side-effect-free elements from an array of expressions. // Returns an array of expressions with side-effects or null // if all elements were dropped. Note: original array may be @@ -2918,31 +3939,29 @@ merge(Compressor.prototype, { } def(AST_Node, return_this); - def(AST_Constant, return_null); - def(AST_This, return_null); - def(AST_Call, function(compressor, first_in_statement){ - if (!this.is_expr_pure(compressor)) { - if (this.expression instanceof AST_Function - && (!this.expression.name || !this.expression.name.definition().references.length)) { - var node = this.clone(); - node.expression.process_expression(false, compressor); - return node; - } + def(AST_Accessor, return_null); + def(AST_Array, function(compressor, first_in_statement) { + var values = trim(this.elements, compressor, first_in_statement); + return values && make_sequence(this, values); + }); + def(AST_Assign, function(compressor) { + var left = this.left; + if (left.has_side_effects(compressor) + || compressor.has_directive("use strict") + && left instanceof AST_PropAccess + && left.expression.is_constant()) { return this; } - if (this.pure) { - compressor.warn("Dropping __PURE__ call [{file}:{line},{col}]", this.start); - this.pure.value = this.pure.value.replace(/[@#]__PURE__/g, ' '); + this.write_only = true; + if (root_expr(left).is_constant_expression(compressor.find_parent(AST_Scope))) { + return this.right.drop_side_effect_free(compressor); } - var args = trim(this.args, compressor, first_in_statement); - return args && make_sequence(this, args); + return this; }); - def(AST_Accessor, return_null); - def(AST_Function, return_null); - def(AST_Binary, function(compressor, first_in_statement){ + def(AST_Binary, function(compressor, first_in_statement) { var right = this.right.drop_side_effect_free(compressor); if (!right) return this.left.drop_side_effect_free(compressor, first_in_statement); - if (lazy_op(this.operator)) { + if (lazy_op[this.operator]) { if (right === this.right) return this; var node = this.clone(); node.right = right; @@ -2953,11 +3972,37 @@ merge(Compressor.prototype, { return make_sequence(this, [ left, right ]); } }); - def(AST_Assign, function(compressor){ - this.write_only = !this.left.has_side_effects(compressor); - return this; + def(AST_Call, function(compressor, first_in_statement) { + if (!this.is_expr_pure(compressor)) { + if (this.expression.is_call_pure(compressor)) { + var exprs = this.args.slice(); + exprs.unshift(this.expression.expression); + exprs = trim(exprs, compressor, first_in_statement); + return exprs && make_sequence(this, exprs); + } + if (this.expression instanceof AST_Function + && (!this.expression.name || !this.expression.name.definition().references.length)) { + var node = this.clone(); + var exp = node.expression; + exp.process_expression(false, compressor); + exp.walk(new TreeWalker(function(node) { + if (node instanceof AST_Return && node.value) { + node.value = node.value.drop_side_effect_free(compressor); + return true; + } + if (node instanceof AST_Scope && node !== exp) return true; + })); + return node; + } + return this; + } + if (this.pure) { + compressor.warn("Dropping __PURE__ call [{file}:{line},{col}]", this.start); + } + var args = trim(this.args, compressor, first_in_statement); + return args && make_sequence(this, args); }); - def(AST_Conditional, function(compressor){ + def(AST_Conditional, function(compressor) { var consequent = this.consequent.drop_side_effect_free(compressor); var alternative = this.alternative.drop_side_effect_free(compressor); if (consequent === this.consequent && alternative === this.alternative) return this; @@ -2976,43 +4021,43 @@ merge(Compressor.prototype, { node.alternative = alternative; return node; }); - def(AST_Unary, function(compressor, first_in_statement){ - if (unary_side_effects(this.operator)) { + def(AST_Constant, return_null); + def(AST_Dot, function(compressor, first_in_statement) { + if (this.expression.may_throw_on_access(compressor)) return this; + return this.expression.drop_side_effect_free(compressor, first_in_statement); + }); + def(AST_Function, function(compressor) { + return this.name && compressor.option("ie8") ? this : null; + }); + def(AST_Unary, function(compressor, first_in_statement) { + if (unary_side_effects[this.operator]) { this.write_only = !this.expression.has_side_effects(compressor); return this; } if (this.operator == "typeof" && this.expression instanceof AST_SymbolRef) return null; var expression = this.expression.drop_side_effect_free(compressor, first_in_statement); - if (first_in_statement - && this instanceof AST_UnaryPrefix - && is_iife_call(expression)) { - if (expression === this.expression && this.operator.length === 1) return this; - return make_node(AST_UnaryPrefix, this, { - operator: this.operator.length === 1 ? this.operator : "!", - expression: expression - }); + if (first_in_statement && expression && is_iife_call(expression)) { + if (expression === this.expression && this.operator == "!") return this; + return expression.negate(compressor, first_in_statement); } return expression; }); - def(AST_SymbolRef, function(compressor) { - return this.is_declared(compressor) ? null : this; - }); - def(AST_Object, function(compressor, first_in_statement){ + def(AST_Object, function(compressor, first_in_statement) { var values = trim(this.properties, compressor, first_in_statement); return values && make_sequence(this, values); }); - def(AST_ObjectProperty, function(compressor, first_in_statement){ + def(AST_ObjectProperty, function(compressor, first_in_statement) { return this.value.drop_side_effect_free(compressor, first_in_statement); }); - def(AST_Array, function(compressor, first_in_statement){ - var values = trim(this.elements, compressor, first_in_statement); - return values && make_sequence(this, values); - }); - def(AST_Dot, function(compressor, first_in_statement){ - if (this.expression.may_throw_on_access(compressor)) return this; - return this.expression.drop_side_effect_free(compressor, first_in_statement); + def(AST_Sequence, function(compressor) { + var last = this.tail_node(); + var expr = last.drop_side_effect_free(compressor); + if (expr === last) return this; + var expressions = this.expressions.slice(0, -1); + if (expr) expressions.push(expr); + return make_sequence(this, expressions); }); - def(AST_Sub, function(compressor, first_in_statement){ + def(AST_Sub, function(compressor, first_in_statement) { if (this.expression.may_throw_on_access(compressor)) return this; var expression = this.expression.drop_side_effect_free(compressor, first_in_statement); if (!expression) return this.property.drop_side_effect_free(compressor, first_in_statement); @@ -3020,19 +4065,15 @@ merge(Compressor.prototype, { if (!property) return expression; return make_sequence(this, [ expression, property ]); }); - def(AST_Sequence, function(compressor){ - var last = this.tail_node(); - var expr = last.drop_side_effect_free(compressor); - if (expr === last) return this; - var expressions = this.expressions.slice(0, -1); - if (expr) expressions.push(expr); - return make_sequence(this, expressions); + def(AST_SymbolRef, function(compressor) { + return this.is_declared(compressor) ? null : this; }); - })(function(node, func){ + def(AST_This, return_null); + })(function(node, func) { node.DEFMETHOD("drop_side_effect_free", func); }); - OPT(AST_SimpleStatement, function(self, compressor){ + OPT(AST_SimpleStatement, function(self, compressor) { if (compressor.option("side_effects")) { var body = self.body; var node = body.drop_side_effect_free(compressor, true); @@ -3047,13 +4088,27 @@ merge(Compressor.prototype, { return self; }); - OPT(AST_While, function(self, compressor){ + OPT(AST_While, function(self, compressor) { return compressor.option("loops") ? make_node(AST_For, self, self).optimize(compressor) : self; }); - OPT(AST_Do, function(self, compressor){ + function has_break_or_continue(loop, parent) { + var found = false; + var tw = new TreeWalker(function(node) { + if (found || node instanceof AST_Scope) return true; + if (node instanceof AST_LoopControl && tw.loopcontrol_target(node) === loop) { + return found = true; + } + }); + if (parent instanceof AST_LabeledStatement) tw.push(parent); + tw.push(loop); + loop.body.walk(tw); + return found; + } + + OPT(AST_Do, function(self, compressor) { if (!compressor.option("loops")) return self; - var cond = self.condition.tail_node().evaluate(compressor); + var cond = self.condition.is_truthy() || self.condition.tail_node().evaluate(compressor); if (!(cond instanceof AST_Node)) { if (cond) return make_node(AST_For, self, { body: make_node(AST_BlockStatement, self.body, { @@ -3065,44 +4120,50 @@ merge(Compressor.prototype, { ] }) }).optimize(compressor); - var has_loop_control = false; - var tw = new TreeWalker(function(node) { - if (node instanceof AST_Scope || has_loop_control) return true; - if (node instanceof AST_LoopControl && tw.loopcontrol_target(node) === self) - return has_loop_control = true; - }); - var parent = compressor.parent(); - (parent instanceof AST_LabeledStatement ? parent : self).walk(tw); - if (!has_loop_control) return make_node(AST_BlockStatement, self.body, { - body: [ - self.body, - make_node(AST_SimpleStatement, self.condition, { - body: self.condition - }) - ] - }).optimize(compressor); + if (!has_break_or_continue(self, compressor.parent())) { + return make_node(AST_BlockStatement, self.body, { + body: [ + self.body, + make_node(AST_SimpleStatement, self.condition, { + body: self.condition + }) + ] + }).optimize(compressor); + } } + if (self.body instanceof AST_SimpleStatement) return make_node(AST_For, self, { + condition: make_sequence(self.condition, [ + self.body.body, + self.condition + ]), + body: make_node(AST_EmptyStatement, self) + }).optimize(compressor); return self; }); function if_break_in_loop(self, compressor) { - function drop_it(rest) { - rest = as_statement_array(rest); - if (self.body instanceof AST_BlockStatement) { - self.body = self.body.clone(); - self.body.body = rest.concat(self.body.body.slice(1)); - self.body = self.body.transform(compressor); - } else { - self.body = make_node(AST_BlockStatement, self.body, { - body: rest - }).transform(compressor); + var first = self.body instanceof AST_BlockStatement ? self.body.body[0] : self.body; + if (compressor.option("dead_code") && is_break(first)) { + var body = []; + if (self.init instanceof AST_Statement) { + body.push(self.init); + } else if (self.init) { + body.push(make_node(AST_SimpleStatement, self.init, { + body: self.init + })); + } + if (self.condition) { + body.push(make_node(AST_SimpleStatement, self.condition, { + body: self.condition + })); } - if_break_in_loop(self, compressor); + extract_declarations_from_unreachable_code(compressor, self.body, body); + return make_node(AST_BlockStatement, self, { + body: body + }); } - var first = self.body instanceof AST_BlockStatement ? self.body.body[0] : self.body; if (first instanceof AST_If) { - if (first.body instanceof AST_Break - && compressor.loopcontrol_target(first.body) === compressor.self()) { + if (is_break(first.body)) { if (self.condition) { self.condition = make_node(AST_Binary, self.condition, { left: self.condition, @@ -3113,9 +4174,7 @@ merge(Compressor.prototype, { self.condition = first.condition.negate(compressor); } drop_it(first.alternative); - } - else if (first.alternative instanceof AST_Break - && compressor.loopcontrol_target(first.alternative) === compressor.self()) { + } else if (is_break(first.alternative)) { if (self.condition) { self.condition = make_node(AST_Binary, self.condition, { left: self.condition, @@ -3128,9 +4187,29 @@ merge(Compressor.prototype, { drop_it(first.body); } } - }; + return self; + + function is_break(node) { + return node instanceof AST_Break + && compressor.loopcontrol_target(node) === compressor.self(); + } + + function drop_it(rest) { + rest = as_statement_array(rest); + if (self.body instanceof AST_BlockStatement) { + self.body = self.body.clone(); + self.body.body = rest.concat(self.body.body.slice(1)); + self.body = self.body.transform(compressor); + } else { + self.body = make_node(AST_BlockStatement, self.body, { + body: rest + }).transform(compressor); + } + self = if_break_in_loop(self, compressor); + } + } - OPT(AST_For, function(self, compressor){ + OPT(AST_For, function(self, compressor) { if (!compressor.option("loops")) return self; if (compressor.option("side_effects") && self.init) { self.init = self.init.drop_side_effect_free(compressor); @@ -3145,9 +4224,11 @@ merge(Compressor.prototype, { self.condition = best_of_expression(self.condition.transform(compressor), orig); } } - if (compressor.option("dead_code")) { - if (cond instanceof AST_Node) cond = self.condition.tail_node().evaluate(compressor); - if (!cond) { + if (cond instanceof AST_Node) { + cond = self.condition.is_truthy() || self.condition.tail_node().evaluate(compressor); + } + if (!cond) { + if (compressor.option("dead_code")) { var body = []; extract_declarations_from_unreachable_code(compressor, self.body, body); if (self.init instanceof AST_Statement) { @@ -3162,13 +4243,22 @@ merge(Compressor.prototype, { })); return make_node(AST_BlockStatement, self, { body: body }).optimize(compressor); } + } else if (self.condition && !(cond instanceof AST_Node)) { + self.body = make_node(AST_BlockStatement, self.body, { + body: [ + make_node(AST_SimpleStatement, self.condition, { + body: self.condition + }), + self.body + ] + }); + self.condition = null; } } - if_break_in_loop(self, compressor); - return self; + return if_break_in_loop(self, compressor); }); - OPT(AST_If, function(self, compressor){ + OPT(AST_If, function(self, compressor) { if (is_empty(self.alternative)) self.alternative = null; if (!compressor.option("conditionals")) return self; @@ -3183,7 +4273,9 @@ merge(Compressor.prototype, { self.condition = best_of_expression(self.condition.transform(compressor), orig); } if (compressor.option("dead_code")) { - if (cond instanceof AST_Node) cond = self.condition.tail_node().evaluate(compressor); + if (cond instanceof AST_Node) { + cond = self.condition.is_truthy() || self.condition.tail_node().evaluate(compressor); + } if (!cond) { compressor.warn("Condition always false [{file}:{line},{col}]", self.condition.start); var body = []; @@ -3312,7 +4404,7 @@ merge(Compressor.prototype, { return self; }); - OPT(AST_Switch, function(self, compressor){ + OPT(AST_Switch, function(self, compressor) { if (!compressor.option("switches")) return self; var branch; var value = self.expression.evaluate(compressor); @@ -3418,12 +4510,23 @@ merge(Compressor.prototype, { } }); - OPT(AST_Try, function(self, compressor){ + OPT(AST_Try, function(self, compressor) { tighten_body(self.body, compressor); if (self.bcatch && self.bfinally && all(self.bfinally.body, is_empty)) self.bfinally = null; - if (all(self.body, is_empty)) { + if (compressor.option("dead_code") && all(self.body, is_empty)) { var body = []; - if (self.bcatch) extract_declarations_from_unreachable_code(compressor, self.bcatch, body); + if (self.bcatch) { + extract_declarations_from_unreachable_code(compressor, self.bcatch, body); + body.forEach(function(stat) { + if (!(stat instanceof AST_Definitions)) return; + stat.definitions.forEach(function(var_def) { + var def = var_def.name.definition().redefined(); + if (!def) return; + var_def.name = var_def.name.clone(); + var_def.name.thedef = def; + }); + }); + } if (self.bfinally) body = body.concat(self.bfinally.body); return make_node(AST_BlockStatement, self, { body: body @@ -3432,13 +4535,15 @@ merge(Compressor.prototype, { return self; }); - AST_Definitions.DEFMETHOD("remove_initializers", function(){ - this.definitions.forEach(function(def){ def.value = null }); + AST_Definitions.DEFMETHOD("remove_initializers", function() { + this.definitions.forEach(function(def) { + def.value = null; + }); }); - AST_Definitions.DEFMETHOD("to_assignments", function(compressor){ + AST_Definitions.DEFMETHOD("to_assignments", function(compressor) { var reduce_vars = compressor.option("reduce_vars"); - var assignments = this.definitions.reduce(function(a, def){ + var assignments = this.definitions.reduce(function(a, def) { if (def.value) { var name = make_node(AST_SymbolRef, def.name, def.name); a.push(make_node(AST_Assign, def, { @@ -3457,22 +4562,40 @@ merge(Compressor.prototype, { return make_sequence(this, assignments); }); - OPT(AST_Definitions, function(self, compressor){ + OPT(AST_Definitions, function(self, compressor) { if (self.definitions.length == 0) return make_node(AST_EmptyStatement, self); return self; }); - OPT(AST_Call, function(self, compressor){ + AST_Call.DEFMETHOD("lift_sequences", function(compressor) { + if (!compressor.option("sequences")) return this; + var exp = this.expression; + if (!(exp instanceof AST_Sequence)) return this; + var tail = exp.tail_node(); + if (needs_unbinding(compressor, tail) && !(this instanceof AST_New)) return this; + var expressions = exp.expressions.slice(0, -1); + var node = this.clone(); + node.expression = tail; + expressions.push(node); + return make_sequence(this, expressions).optimize(compressor); + }); + + OPT(AST_Call, function(self, compressor) { + var seq = self.lift_sequences(compressor); + if (seq !== self) { + return seq; + } var exp = self.expression; var fn = exp; if (compressor.option("reduce_vars") && fn instanceof AST_SymbolRef) { fn = fn.fixed_value(); } + var is_func = fn instanceof AST_Lambda; if (compressor.option("unused") - && fn instanceof AST_Function + && is_func && !fn.uses_arguments - && !fn.uses_eval) { + && !fn.pinned()) { var pos = 0, last = 0; for (var i = 0, len = self.args.length; i < len; i++) { var trim = i >= fn.argnames.length; @@ -3537,13 +4660,36 @@ merge(Compressor.prototype, { operator: "!" }).optimize(compressor); break; + case "RegExp": + var params = []; + if (all(self.args, function(arg) { + var value = arg.evaluate(compressor); + params.unshift(value); + return arg !== value; + })) { + try { + return best_of(compressor, self, make_node(AST_RegExp, self, { + value: RegExp.apply(RegExp, params), + })); + } catch (ex) { + compressor.warn("Error converting {expr} [{file}:{line},{col}]", { + expr: self.print_to_string(), + file: self.start.file, + line: self.start.line, + col: self.start.col + }); + } + } + break; } else if (exp instanceof AST_Dot) switch(exp.property) { case "toString": - if (self.args.length == 0) return make_node(AST_Binary, self, { - left: make_node(AST_String, self, { value: "" }), - operator: "+", - right: exp.expression - }).optimize(compressor); + if (self.args.length == 0 && !exp.expression.may_throw_on_access(compressor)) { + return make_node(AST_Binary, self, { + left: make_node(AST_String, self, { value: "" }), + operator: "+", + right: exp.expression + }).optimize(compressor); + } break; case "join": if (exp.expression instanceof AST_Array) EXIT: { @@ -3592,7 +4738,7 @@ merge(Compressor.prototype, { } else { first = make_node(AST_String, self, { value: "" }); } - return elements.reduce(function(prev, el){ + return elements.reduce(function(prev, el) { return make_node(AST_Binary, el, { operator : "+", left : prev, @@ -3621,9 +4767,40 @@ merge(Compressor.prototype, { } } break; + case "apply": + if (self.args.length == 2 && self.args[1] instanceof AST_Array) { + var args = self.args[1].elements.slice(); + args.unshift(self.args[0]); + return make_node(AST_Call, self, { + expression: make_node(AST_Dot, exp, { + expression: exp.expression, + property: "call" + }), + args: args + }).optimize(compressor); + } + break; + case "call": + var func = exp.expression; + if (func instanceof AST_SymbolRef) { + func = func.fixed_value(); + } + if (func instanceof AST_Lambda && !func.contains_this()) { + return (self.args.length ? make_sequence(this, [ + self.args[0], + make_node(AST_Call, self, { + expression: exp.expression, + args: self.args.slice(1) + }) + ]) : make_node(AST_Call, self, { + expression: exp.expression, + args: [] + })).optimize(compressor); + } + break; } } - if (compressor.option("unsafe_Func") + if (compressor.option("unsafe_Function") && is_undeclared_ref(exp) && exp.name == "Function") { // new Function() => function(){} @@ -3647,7 +4824,6 @@ merge(Compressor.prototype, { var comp = new Compressor(compressor.options); ast = ast.transform(comp); ast.figure_out_scope(mangle); - base54.reset(); ast.compute_char_frequency(mangle); ast.mangle_names(mangle); var fun; @@ -3681,39 +4857,37 @@ merge(Compressor.prototype, { } } } - var stat = fn instanceof AST_Function && fn.body[0]; - if (compressor.option("inline") && stat instanceof AST_Return) { + var stat = is_func && fn.body[0]; + var can_inline = compressor.option("inline") && !self.is_expr_pure(compressor); + if (can_inline && stat instanceof AST_Return) { var value = stat.value; if (!value || value.is_constant_expression()) { - var args = self.args.concat(value || make_node(AST_Undefined, self)); + if (value) { + value = value.clone(true); + } else { + value = make_node(AST_Undefined, self); + } + var args = self.args.concat(value); return make_sequence(self, args).optimize(compressor); } } - if (fn instanceof AST_Function) { - if (compressor.option("inline") - && exp === fn - && !fn.name + if (is_func) { + var def, value, scope, in_loop, level = -1; + if (can_inline && !fn.uses_arguments - && !fn.uses_eval - && fn.body.length == 1 + && !fn.pinned() + && !(fn.name && fn instanceof AST_Function) + && (value = can_flatten_body(stat)) + && (exp === fn + || compressor.option("unused") + && (def = exp.definition()).references.length == 1 + && !recursive_ref(compressor, def) + && fn.is_constant_expression(exp.scope)) + && !self.pure && !fn.contains_this() - && all(fn.argnames, function(arg) { - return arg.__unused; - }) - && !self.has_pure_annotation(compressor)) { - var value; - if (stat instanceof AST_Return) { - value = stat.value; - } else if (stat instanceof AST_SimpleStatement) { - value = make_node(AST_UnaryPrefix, stat, { - operator: "void", - expression: stat.body - }); - } - if (value) { - var args = self.args.concat(value); - return make_sequence(self, args).optimize(compressor); - } + && can_inject_symbols()) { + fn._squeezed = true; + return make_sequence(self, flatten_fn()).optimize(compressor); } if (compressor.option("side_effects") && all(fn.body, is_empty)) { var args = self.args.concat(make_node(AST_Undefined, self)); @@ -3742,9 +4916,191 @@ merge(Compressor.prototype, { return best_of(compressor, ev, self); } return self; + + function return_value(stat) { + if (!stat) return make_node(AST_Undefined, self); + if (stat instanceof AST_Return) { + if (!stat.value) return make_node(AST_Undefined, self); + return stat.value.clone(true); + } + if (stat instanceof AST_SimpleStatement) { + return make_node(AST_UnaryPrefix, stat, { + operator: "void", + expression: stat.body.clone(true) + }); + } + } + + function can_flatten_body(stat) { + var len = fn.body.length; + if (compressor.option("inline") < 3) { + return len == 1 && return_value(stat); + } + stat = null; + for (var i = 0; i < len; i++) { + var line = fn.body[i]; + if (line instanceof AST_Var) { + if (stat && !all(line.definitions, function(var_def) { + return !var_def.value; + })) { + return false; + } + } else if (line instanceof AST_EmptyStatement) { + continue; + } else if (stat) { + return false; + } else { + stat = line; + } + } + return return_value(stat); + } + + function can_inject_args(catches, safe_to_inject) { + for (var i = 0, len = fn.argnames.length; i < len; i++) { + var arg = fn.argnames[i]; + if (arg.__unused) continue; + if (!safe_to_inject + || catches[arg.name] + || identifier_atom[arg.name] + || scope.var_names()[arg.name]) { + return false; + } + if (in_loop) in_loop.push(arg.definition()); + } + return true; + } + + function can_inject_vars(catches, safe_to_inject) { + var len = fn.body.length; + for (var i = 0; i < len; i++) { + var stat = fn.body[i]; + if (!(stat instanceof AST_Var)) continue; + if (!safe_to_inject) return false; + for (var j = stat.definitions.length; --j >= 0;) { + var name = stat.definitions[j].name; + if (catches[name.name] + || identifier_atom[name.name] + || scope.var_names()[name.name]) { + return false; + } + if (in_loop) in_loop.push(name.definition()); + } + } + return true; + } + + function can_inject_symbols() { + var catches = Object.create(null); + do { + scope = compressor.parent(++level); + if (scope instanceof AST_Catch) { + catches[scope.argname.name] = true; + } else if (scope instanceof AST_IterationStatement) { + in_loop = []; + } else if (scope instanceof AST_SymbolRef) { + if (scope.fixed_value() instanceof AST_Scope) return false; + } + } while (!(scope instanceof AST_Scope)); + var safe_to_inject = !(scope instanceof AST_Toplevel) || compressor.toplevel.vars; + var inline = compressor.option("inline"); + if (!can_inject_vars(catches, inline >= 3 && safe_to_inject)) return false; + if (!can_inject_args(catches, inline >= 2 && safe_to_inject)) return false; + return !in_loop || in_loop.length == 0 || !is_reachable(fn, in_loop); + } + + function append_var(decls, expressions, name, value) { + var def = name.definition(); + scope.variables.set(name.name, def); + scope.enclosed.push(def); + if (!scope.var_names()[name.name]) { + scope.var_names()[name.name] = true; + decls.push(make_node(AST_VarDef, name, { + name: name, + value: null + })); + } + var sym = make_node(AST_SymbolRef, name, name); + def.references.push(sym); + if (value) expressions.push(make_node(AST_Assign, self, { + operator: "=", + left: sym, + right: value + })); + } + + function flatten_args(decls, expressions) { + var len = fn.argnames.length; + for (var i = self.args.length; --i >= len;) { + expressions.push(self.args[i]); + } + for (i = len; --i >= 0;) { + var name = fn.argnames[i]; + var value = self.args[i]; + if (name.__unused || scope.var_names()[name.name]) { + if (value) expressions.push(value); + } else { + var symbol = make_node(AST_SymbolVar, name, name); + name.definition().orig.push(symbol); + if (!value && in_loop) value = make_node(AST_Undefined, self); + append_var(decls, expressions, symbol, value); + } + } + decls.reverse(); + expressions.reverse(); + } + + function flatten_vars(decls, expressions) { + var pos = expressions.length; + for (var i = 0, lines = fn.body.length; i < lines; i++) { + var stat = fn.body[i]; + if (!(stat instanceof AST_Var)) continue; + for (var j = 0, defs = stat.definitions.length; j < defs; j++) { + var var_def = stat.definitions[j]; + var name = var_def.name; + var redef = name.definition().redefined(); + if (redef) { + name = name.clone(); + name.thedef = redef; + } + append_var(decls, expressions, name, var_def.value); + if (in_loop && all(fn.argnames, function(argname) { + return argname.name != name.name; + })) { + var def = fn.variables.get(name.name); + var sym = make_node(AST_SymbolRef, name, name); + def.references.push(sym); + expressions.splice(pos++, 0, make_node(AST_Assign, var_def, { + operator: "=", + left: sym, + right: make_node(AST_Undefined, name) + })); + } + } + } + } + + function flatten_fn() { + var decls = []; + var expressions = []; + flatten_args(decls, expressions); + flatten_vars(decls, expressions); + expressions.push(value); + if (decls.length) { + i = scope.body.indexOf(compressor.parent(level - 1)) + 1; + scope.body.splice(i, 0, make_node(AST_Var, fn, { + definitions: decls + })); + } + return expressions; + } }); - OPT(AST_New, function(self, compressor){ + OPT(AST_New, function(self, compressor) { + var seq = self.lift_sequences(compressor); + if (seq !== self) { + return seq; + } if (compressor.option("unsafe")) { var exp = self.expression; if (is_undeclared_ref(exp)) { @@ -3761,15 +5117,14 @@ merge(Compressor.prototype, { return self; }); - OPT(AST_Sequence, function(self, compressor){ + OPT(AST_Sequence, function(self, compressor) { if (!compressor.option("side_effects")) return self; var expressions = []; filter_for_side_effects(); var end = expressions.length - 1; trim_right_for_undefined(); - if (end > 0 && compressor.option("cascade")) trim_left_for_assignment(); if (end == 0) { - self = maintain_this_binding(compressor.parent(), compressor.self(), expressions[0]); + self = maintain_this_binding(compressor, compressor.parent(), compressor.self(), expressions[0]); if (!(self instanceof AST_Sequence)) self = self.optimize(compressor); return self; } @@ -3798,91 +5153,24 @@ merge(Compressor.prototype, { expressions.length = end + 1; } } - - function trim_left_for_assignment() { - for (var i = 0, j = 1; j <= end; j++) { - var left = expressions[i]; - var cdr = expressions[j]; - if (left instanceof AST_Assign - && !left.left.has_side_effects(compressor)) { - left = left.left; - } else if (left instanceof AST_Unary - && (left.operator == "++" || left.operator == "--")) { - left = left.expression; - } else left = null; - if (!left || is_lhs_read_only(left) || left.has_side_effects(compressor)) { - expressions[++i] = cdr; - continue; - } - var parent = null, field; - expressions[j] = cdr = cdr.clone(); - while (true) { - if (cdr.equivalent_to(left)) { - var car = expressions[i]; - if (car instanceof AST_UnaryPostfix) { - car = make_node(AST_UnaryPrefix, car, { - operator: car.operator, - expression: left - }); - } else { - car.write_only = false; - } - if (parent) { - parent[field] = car; - expressions[i] = expressions[j]; - } else { - expressions[i] = car; - } - break; - } - if (cdr instanceof AST_Binary && !(cdr instanceof AST_Assign)) { - if (cdr.left.is_constant()) { - if (lazy_op(cdr.operator)) { - expressions[++i] = expressions[j]; - break; - } - field = "right"; - } else { - field = "left"; - } - } else if (cdr instanceof AST_Call - && !(left instanceof AST_PropAccess && cdr.expression.equivalent_to(left)) - || cdr instanceof AST_PropAccess - || cdr instanceof AST_Unary && !unary_side_effects(cdr.operator)) { - field = "expression"; - } else if (cdr instanceof AST_Conditional) { - field = "condition"; - } else { - expressions[++i] = expressions[j]; - break; - } - parent = cdr; - cdr = cdr[field] = cdr[field].clone(); - } - } - end = i; - expressions.length = end + 1; - } }); - AST_Unary.DEFMETHOD("lift_sequences", function(compressor){ - if (compressor.option("sequences")) { - if (this.expression instanceof AST_Sequence) { - var x = this.expression.expressions.slice(); - var e = this.clone(); - e.expression = x.pop(); - x.push(e); - return make_sequence(this, x).optimize(compressor); - } + AST_Unary.DEFMETHOD("lift_sequences", function(compressor) { + if (compressor.option("sequences") && this.expression instanceof AST_Sequence) { + var x = this.expression.expressions.slice(); + var e = this.clone(); + e.expression = x.pop(); + x.push(e); + return make_sequence(this, x).optimize(compressor); } return this; }); - OPT(AST_UnaryPostfix, function(self, compressor){ + OPT(AST_UnaryPostfix, function(self, compressor) { return self.lift_sequences(compressor); }); - OPT(AST_UnaryPrefix, function(self, compressor){ + OPT(AST_UnaryPrefix, function(self, compressor) { var e = self.expression; if (self.operator == "delete" && !(e instanceof AST_SymbolRef @@ -3908,8 +5196,10 @@ merge(Compressor.prototype, { return make_node(AST_Undefined, self).optimize(compressor); } } - if (compressor.in_boolean_context()) { - switch (self.operator) { + if (compressor.option("booleans")) { + if (self.operator == "!" && e.is_truthy()) { + return make_sequence(self, [ e, make_node(AST_False, self) ]).optimize(compressor); + } else if (compressor.in_boolean_context()) switch (self.operator) { case "!": if (e instanceof AST_UnaryPrefix && e.operator == "!") { // !!foo ==> foo, if we're in boolean context @@ -3956,7 +5246,7 @@ merge(Compressor.prototype, { return self; }); - AST_Binary.DEFMETHOD("lift_sequences", function(compressor){ + AST_Binary.DEFMETHOD("lift_sequences", function(compressor) { if (compressor.option("sequences")) { if (this.left instanceof AST_Sequence) { var x = this.left.expressions.slice(); @@ -3997,7 +5287,7 @@ merge(Compressor.prototype, { || node instanceof AST_Object; } - OPT(AST_Binary, function(self, compressor){ + OPT(AST_Binary, function(self, compressor) { function reversible() { return self.left.is_constant() || self.right.is_constant() @@ -4012,7 +5302,7 @@ merge(Compressor.prototype, { self.right = tmp; } } - if (commutativeOperators(self.operator)) { + if (commutativeOperators[self.operator]) { if (self.right.is_constant() && !self.left.is_constant()) { // if right is a constant, whatever side effects the @@ -4029,17 +5319,22 @@ merge(Compressor.prototype, { if (compressor.option("comparisons")) switch (self.operator) { case "===": case "!==": + var is_strict_comparison = true; if ((self.left.is_string(compressor) && self.right.is_string(compressor)) || (self.left.is_number(compressor) && self.right.is_number(compressor)) || - (self.left.is_boolean() && self.right.is_boolean()) || + (self.left.is_boolean(compressor) && self.right.is_boolean(compressor)) || self.left.equivalent_to(self.right)) { self.operator = self.operator.substr(0, 2); } // XXX: intentionally falling down to the next case case "==": case "!=": + // void 0 == x => null == x + if (!is_strict_comparison && is_undefined(self.left, compressor)) { + self.left = make_node(AST_Null, self.left); + } // "undefined" == typeof x => undefined === x - if (compressor.option("typeofs") + else if (compressor.option("typeofs") && self.left instanceof AST_String && self.left.value == "undefined" && self.right instanceof AST_UnaryPrefix @@ -4060,8 +5355,37 @@ merge(Compressor.prototype, { return make_node(self.operator[0] == "=" ? AST_True : AST_False, self); } break; + case "&&": + case "||": + var lhs = self.left; + if (lhs.operator == self.operator) { + lhs = lhs.right; + } + if (lhs instanceof AST_Binary + && lhs.operator == (self.operator == "&&" ? "!==" : "===") + && self.right instanceof AST_Binary + && lhs.operator == self.right.operator + && (is_undefined(lhs.left, compressor) && self.right.left instanceof AST_Null + || lhs.left instanceof AST_Null && is_undefined(self.right.left, compressor)) + && !lhs.right.has_side_effects(compressor) + && lhs.right.equivalent_to(self.right.right)) { + var combined = make_node(AST_Binary, self, { + operator: lhs.operator.slice(0, -1), + left: make_node(AST_Null, self), + right: lhs.right + }); + if (lhs !== self.left) { + combined = make_node(AST_Binary, self, { + operator: self.operator, + left: self.left.left, + right: combined + }); + } + return combined; + } + break; } - if (self.operator == "+" && compressor.in_boolean_context()) { + if (compressor.option("booleans") && self.operator == "+" && compressor.in_boolean_context()) { var ll = self.left.evaluate(compressor); var rr = self.right.evaluate(compressor); if (ll && typeof ll == "string") { @@ -4079,7 +5403,7 @@ merge(Compressor.prototype, { ]).optimize(compressor); } } - if (compressor.option("comparisons") && self.is_boolean()) { + if (compressor.option("comparisons") && self.is_boolean(compressor)) { if (!(compressor.parent() instanceof AST_Binary) || compressor.parent() instanceof AST_Assign) { var negated = make_node(AST_UnaryPrefix, self, { @@ -4088,11 +5412,9 @@ merge(Compressor.prototype, { }); self = best_of(compressor, self, negated); } - if (compressor.option("unsafe_comps")) { - switch (self.operator) { - case "<": reverse(">"); break; - case "<=": reverse(">="); break; - } + switch (self.operator) { + case ">": reverse("<"); break; + case ">=": reverse("<="); break; } } if (self.operator == "+") { @@ -4118,17 +5440,17 @@ merge(Compressor.prototype, { if (compressor.option("evaluate")) { switch (self.operator) { case "&&": - var ll = self.left.truthy ? true : self.left.falsy ? false : self.left.evaluate(compressor); + var ll = fuzzy_eval(self.left); if (!ll) { compressor.warn("Condition left of && always false [{file}:{line},{col}]", self.start); - return maintain_this_binding(compressor.parent(), compressor.self(), self.left).optimize(compressor); + return maintain_this_binding(compressor, compressor.parent(), compressor.self(), self.left).optimize(compressor); } else if (!(ll instanceof AST_Node)) { compressor.warn("Condition left of && always true [{file}:{line},{col}]", self.start); return make_sequence(self, [ self.left, self.right ]).optimize(compressor); } var rr = self.right.evaluate(compressor); if (!rr) { - if (compressor.in_boolean_context()) { + if (compressor.option("booleans") && compressor.in_boolean_context()) { compressor.warn("Boolean && always false [{file}:{line},{col}]", self.start); return make_sequence(self, [ self.left, @@ -4137,7 +5459,8 @@ merge(Compressor.prototype, { } else self.falsy = true; } else if (!(rr instanceof AST_Node)) { var parent = compressor.parent(); - if (parent.operator == "&&" && parent.left === compressor.self() || compressor.in_boolean_context()) { + if (parent.operator == "&&" && parent.left === compressor.self() + || compressor.option("booleans") && compressor.in_boolean_context()) { compressor.warn("Dropping side-effect-free && [{file}:{line},{col}]", self.start); return self.left.optimize(compressor); } @@ -4153,23 +5476,24 @@ merge(Compressor.prototype, { } break; case "||": - var ll = self.left.truthy ? true : self.left.falsy ? false : self.left.evaluate(compressor); + var ll = fuzzy_eval(self.left); if (!ll) { compressor.warn("Condition left of || always false [{file}:{line},{col}]", self.start); return make_sequence(self, [ self.left, self.right ]).optimize(compressor); } else if (!(ll instanceof AST_Node)) { compressor.warn("Condition left of || always true [{file}:{line},{col}]", self.start); - return maintain_this_binding(compressor.parent(), compressor.self(), self.left).optimize(compressor); + return maintain_this_binding(compressor, compressor.parent(), compressor.self(), self.left).optimize(compressor); } var rr = self.right.evaluate(compressor); if (!rr) { var parent = compressor.parent(); - if (parent.operator == "||" && parent.left === compressor.self() || compressor.in_boolean_context()) { + if (parent.operator == "||" && parent.left === compressor.self() + || compressor.option("booleans") && compressor.in_boolean_context()) { compressor.warn("Dropping side-effect-free || [{file}:{line},{col}]", self.start); return self.left.optimize(compressor); } } else if (!(rr instanceof AST_Node)) { - if (compressor.in_boolean_context()) { + if (compressor.option("booleans") && compressor.in_boolean_context()) { compressor.warn("Boolean || always true [{file}:{line},{col}]", self.start); return make_sequence(self, [ self.left, @@ -4371,7 +5695,7 @@ merge(Compressor.prototype, { // "x" + (y + "z")==> "x" + y + "z" if (self.right instanceof AST_Binary && self.right.operator == self.operator - && (lazy_op(self.operator) + && (lazy_op[self.operator] || (self.operator == "+" && (self.right.left.is_string(compressor) || (self.left.is_string(compressor) @@ -4391,6 +5715,13 @@ merge(Compressor.prototype, { return best_of(compressor, ev, self); } return self; + + function fuzzy_eval(node) { + if (node.truthy) return true; + if (node.falsy) return false; + if (node.is_truthy()) return true; + return node.evaluate(compressor); + } }); function recursive_ref(compressor, def) { @@ -4404,15 +5735,11 @@ merge(Compressor.prototype, { return node; } - OPT(AST_SymbolRef, function(self, compressor){ - var def = self.resolve_defines(compressor); - if (def) { - return def.optimize(compressor); - } - // testing against !self.scope.uses_with first is an optimization + OPT(AST_SymbolRef, function(self, compressor) { if (!compressor.option("ie8") && is_undeclared_ref(self) - && (!self.scope.uses_with || !compressor.find_parent(AST_With))) { + // testing against `self.scope.uses_with` is an optimization + && !(self.scope.uses_with && compressor.find_parent(AST_With))) { switch (self.name) { case "undefined": return make_node(AST_Undefined, self).optimize(compressor); @@ -4422,44 +5749,68 @@ merge(Compressor.prototype, { return make_node(AST_Infinity, self).optimize(compressor); } } - if (compressor.option("reduce_vars") - && is_lhs(self, compressor.parent()) !== self) { - var d = self.definition(); + var parent = compressor.parent(); + if (compressor.option("reduce_vars") && is_lhs(self, parent) !== self) { + var def = self.definition(); var fixed = self.fixed_value(); - if (fixed instanceof AST_Defun) { - d.fixed = fixed = make_node(AST_Function, fixed, fixed); - } - if (d.single_use && fixed instanceof AST_Function) { - if (d.scope !== self.scope - && (!compressor.option("reduce_funcs") - || d.escaped - || fixed.inlined)) { - d.single_use = false; - } else if (recursive_ref(compressor, d)) { - d.single_use = false; - } else if (d.scope !== self.scope || d.orig[0] instanceof AST_SymbolFunarg) { - d.single_use = fixed.is_constant_expression(self.scope); - if (d.single_use == "f") { + var single_use = def.single_use && !(parent instanceof AST_Call && parent.is_expr_pure(compressor)); + if (single_use && fixed instanceof AST_Lambda) { + if (def.scope !== self.scope + && (!compressor.option("reduce_funcs") || def.escaped == 1 || fixed.inlined)) { + single_use = false; + } else if (recursive_ref(compressor, def)) { + single_use = false; + } else if (def.scope !== self.scope || def.orig[0] instanceof AST_SymbolFunarg) { + single_use = fixed.is_constant_expression(self.scope); + if (single_use == "f") { var scope = self.scope; - do { - if (scope instanceof AST_Defun || scope instanceof AST_Function) { - scope.inlined = true; - } + do if (scope instanceof AST_Defun || scope instanceof AST_Function) { + scope.inlined = true; } while (scope = scope.parent_scope); } } } - if (d.single_use && fixed) { - var value = fixed.optimize(compressor); - return value === fixed ? fixed.clone(true) : value; + if (single_use && fixed) { + def.single_use = false; + if (fixed instanceof AST_Defun) { + fixed._squeezed = true; + fixed = make_node(AST_Function, fixed, fixed); + fixed.name = make_node(AST_SymbolLambda, fixed.name, fixed.name); + } + var value; + if (def.recursive_refs > 0) { + value = fixed.clone(true); + var defun_def = value.name.definition(); + var lambda_def = value.variables.get(value.name.name); + var name = lambda_def && lambda_def.orig[0]; + if (!(name instanceof AST_SymbolLambda)) { + name = make_node(AST_SymbolLambda, value.name, value.name); + name.scope = value; + value.name = name; + lambda_def = value.def_function(name); + } + value.walk(new TreeWalker(function(node) { + if (!(node instanceof AST_SymbolRef)) return; + var def = node.definition(); + if (def === defun_def) { + node.thedef = lambda_def; + lambda_def.references.push(node); + } else { + def.single_use = false; + } + })); + } else { + value = fixed.optimize(compressor); + if (value === fixed) value = fixed.clone(true); + } + return value; } - if (fixed && d.should_replace === undefined) { + if (fixed && def.should_replace === undefined) { var init; if (fixed instanceof AST_This) { - if (!(d.orig[0] instanceof AST_SymbolFunarg) - && all(d.references, function(ref) { - return d.scope === ref.scope; - })) { + if (!(def.orig[0] instanceof AST_SymbolFunarg) && all(def.references, function(ref) { + return def.scope === ref.scope; + })) { init = fixed; } } else { @@ -4483,18 +5834,18 @@ merge(Compressor.prototype, { return result === init || result === fixed ? result.clone(true) : result; }; } - var name_length = d.name.length; + var name_length = def.name.length; var overhead = 0; - if (compressor.option("unused") && !compressor.exposed(d)) { - overhead = (name_length + 2 + value_length) / d.references.length; + if (compressor.option("unused") && !compressor.exposed(def)) { + overhead = (name_length + 2 + value_length) / (def.references.length - def.assignments); } - d.should_replace = value_length <= name_length + overhead ? fn : false; + def.should_replace = value_length <= name_length + overhead ? fn : false; } else { - d.should_replace = false; + def.should_replace = false; } } - if (d.should_replace) { - return d.should_replace(); + if (def.should_replace) { + return def.should_replace(); } } return self; @@ -4513,8 +5864,8 @@ merge(Compressor.prototype, { return lhs instanceof AST_SymbolRef || lhs.TYPE === self.TYPE; } - OPT(AST_Undefined, function(self, compressor){ - if (compressor.option("unsafe")) { + OPT(AST_Undefined, function(self, compressor) { + if (compressor.option("unsafe_undefined")) { var undef = find_variable(compressor, "undefined"); if (undef) { var ref = make_node(AST_SymbolRef, self, { @@ -4536,7 +5887,7 @@ merge(Compressor.prototype, { }); }); - OPT(AST_Infinity, function(self, compressor){ + OPT(AST_Infinity, function(self, compressor) { var lhs = is_lhs(compressor.self(), compressor.parent()); if (lhs && is_atomic(lhs, self)) return self; if (compressor.option("keep_infinity") @@ -4554,7 +5905,7 @@ merge(Compressor.prototype, { }); }); - OPT(AST_NaN, function(self, compressor){ + OPT(AST_NaN, function(self, compressor) { var lhs = is_lhs(compressor.self(), compressor.parent()); if (lhs && !is_atomic(lhs, self) || find_variable(compressor, "NaN")) { @@ -4571,22 +5922,65 @@ merge(Compressor.prototype, { return self; }); - var ASSIGN_OPS = [ '+', '-', '/', '*', '%', '>>', '<<', '>>>', '|', '^', '&' ]; - var ASSIGN_OPS_COMMUTATIVE = [ '*', '|', '^', '&' ]; - OPT(AST_Assign, function(self, compressor){ + function is_reachable(self, defs) { + var reachable = false; + var find_ref = new TreeWalker(function(node) { + if (reachable) return true; + if (node instanceof AST_SymbolRef && member(node.definition(), defs)) { + return reachable = true; + } + }); + var scan_scope = new TreeWalker(function(node) { + if (reachable) return true; + if (node instanceof AST_Scope && node !== self) { + var parent = scan_scope.parent(); + if (parent instanceof AST_Call && parent.expression === node) return; + node.walk(find_ref); + return true; + } + }); + self.walk(scan_scope); + return reachable; + } + + var ASSIGN_OPS = makePredicate("+ - / * % >> << >>> | ^ &"); + var ASSIGN_OPS_COMMUTATIVE = makePredicate("* | ^ &"); + OPT(AST_Assign, function(self, compressor) { + var def; + if (compressor.option("dead_code") + && self.left instanceof AST_SymbolRef + && (def = self.left.definition()).scope === compressor.find_parent(AST_Lambda)) { + var level = 0, node, parent = self; + do { + node = parent; + parent = compressor.parent(level++); + if (parent instanceof AST_Exit) { + if (in_try(level, parent)) break; + if (is_reachable(def.scope, [ def ])) break; + if (self.operator == "=") return self.right; + def.fixed = false; + return make_node(AST_Binary, self, { + operator: self.operator.slice(0, -1), + left: self.left, + right: self.right + }).optimize(compressor); + } + } while (parent instanceof AST_Binary && parent.right === node + || parent instanceof AST_Sequence && parent.tail_node() === node); + } self = self.lift_sequences(compressor); if (self.operator == "=" && self.left instanceof AST_SymbolRef && self.right instanceof AST_Binary) { // x = expr1 OP expr2 if (self.right.left instanceof AST_SymbolRef && self.right.left.name == self.left.name - && member(self.right.operator, ASSIGN_OPS)) { + && ASSIGN_OPS[self.right.operator]) { // x = x - 2 ---> x -= 2 self.operator = self.right.operator + "="; self.right = self.right.right; } else if (self.right.right instanceof AST_SymbolRef && self.right.right.name == self.left.name - && member(self.right.operator, ASSIGN_OPS_COMMUTATIVE) + && ASSIGN_OPS_COMMUTATIVE[self.right.operator] && !self.right.left.has_side_effects(compressor)) { // x = 2 & x ---> x &= 2 self.operator = self.right.operator + "="; @@ -4594,9 +5988,24 @@ merge(Compressor.prototype, { } } return self; + + function in_try(level, node) { + var right = self.right; + self.right = make_node(AST_Null, right); + var may_throw = node.may_throw(compressor); + self.right = right; + var scope = self.left.definition().scope; + var parent; + while ((parent = compressor.parent(level++)) !== scope) { + if (parent instanceof AST_Try) { + if (parent.bfinally) return true; + if (may_throw && parent.bcatch) return true; + } + } + } }); - OPT(AST_Conditional, function(self, compressor){ + OPT(AST_Conditional, function(self, compressor) { if (!compressor.option("conditionals")) return self; // This looks like lift_sequences(), should probably be under "sequences" if (self.condition instanceof AST_Sequence) { @@ -4605,15 +6014,13 @@ merge(Compressor.prototype, { expressions.push(self); return make_sequence(self, expressions); } - var cond = self.condition.evaluate(compressor); - if (cond !== self.condition) { - if (cond) { - compressor.warn("Condition always true [{file}:{line},{col}]", self.start); - return maintain_this_binding(compressor.parent(), compressor.self(), self.consequent); - } else { - compressor.warn("Condition always false [{file}:{line},{col}]", self.start); - return maintain_this_binding(compressor.parent(), compressor.self(), self.alternative); - } + var cond = self.condition.is_truthy() || self.condition.tail_node().evaluate(compressor); + if (!cond) { + compressor.warn("Condition always false [{file}:{line},{col}]", self.start); + return make_sequence(self, [ self.condition, self.alternative ]).optimize(compressor); + } else if (!(cond instanceof AST_Node)) { + compressor.warn("Condition always true [{file}:{line},{col}]", self.start); + return make_sequence(self, [ self.condition, self.consequent ]).optimize(compressor); } var negated = cond.negate(compressor, first_in_statement(compressor)); if (best_of(compressor, cond, negated) === negated) { @@ -4640,22 +6047,26 @@ merge(Compressor.prototype, { // | // v // exp = foo ? something : something_else; - if (consequent instanceof AST_Assign - && alternative instanceof AST_Assign - && consequent.operator == alternative.operator - && consequent.left.equivalent_to(alternative.left) - && (!self.condition.has_side_effects(compressor) - || consequent.operator == "=" - && !consequent.left.has_side_effects(compressor))) { - return make_node(AST_Assign, self, { - operator: consequent.operator, - left: consequent.left, - right: make_node(AST_Conditional, self, { - condition: self.condition, - consequent: consequent.right, - alternative: alternative.right - }) - }); + var seq_tail = consequent.tail_node(); + if (seq_tail instanceof AST_Assign) { + var is_eq = seq_tail.operator == "="; + var alt_tail = is_eq ? alternative.tail_node() : alternative; + if ((is_eq || consequent instanceof AST_Assign) + && alt_tail instanceof AST_Assign + && seq_tail.operator == alt_tail.operator + && seq_tail.left.equivalent_to(alt_tail.left) + && (!condition.has_side_effects(compressor) + || is_eq && !seq_tail.left.has_side_effects(compressor))) { + return make_node(AST_Assign, self, { + operator: seq_tail.operator, + left: seq_tail.left, + right: make_node(AST_Conditional, self, { + condition: condition, + consequent: pop_lhs(consequent), + alternative: pop_lhs(alternative) + }) + }); + } } // x ? y(a) : y(b) --> y(x ? a : b) var arg_index; @@ -4664,12 +6075,12 @@ merge(Compressor.prototype, { && consequent.args.length > 0 && consequent.args.length == alternative.args.length && consequent.expression.equivalent_to(alternative.expression) - && !self.condition.has_side_effects(compressor) + && !condition.has_side_effects(compressor) && !consequent.expression.has_side_effects(compressor) && typeof (arg_index = single_arg_diff()) == "number") { var node = consequent.clone(); node.args[arg_index] = make_node(AST_Conditional, self, { - condition: self.condition, + condition: condition, consequent: consequent.args[arg_index], alternative: alternative.args[arg_index] }); @@ -4680,7 +6091,7 @@ merge(Compressor.prototype, { && consequent.alternative.equivalent_to(alternative)) { return make_node(AST_Conditional, self, { condition: make_node(AST_Binary, self, { - left: self.condition, + left: condition, operator: "&&", right: consequent.condition }), @@ -4691,32 +6102,58 @@ merge(Compressor.prototype, { // x ? y : y --> x, y if (consequent.equivalent_to(alternative)) { return make_sequence(self, [ - self.condition, + condition, consequent ]).optimize(compressor); } - var in_bool = compressor.in_boolean_context(); + // x ? (y, w) : (z, w) --> x ? y : z, w + if ((consequent instanceof AST_Sequence || alternative instanceof AST_Sequence) + && consequent.tail_node().equivalent_to(alternative.tail_node())) { + return make_sequence(self, [ + make_node(AST_Conditional, self, { + condition: condition, + consequent: pop_seq(consequent), + alternative: pop_seq(alternative) + }), + consequent.tail_node() + ]).optimize(compressor); + } + // x ? y || z : z --> x && y || z + if (consequent instanceof AST_Binary + && consequent.operator == "||" + && consequent.right.equivalent_to(alternative)) { + return make_node(AST_Binary, self, { + operator: "||", + left: make_node(AST_Binary, self, { + operator: "&&", + left: condition, + right: consequent.left + }), + right: alternative + }).optimize(compressor); + } + var in_bool = compressor.option("booleans") && compressor.in_boolean_context(); if (is_true(self.consequent)) { if (is_false(self.alternative)) { // c ? true : false ---> !!c - return booleanize(self.condition); + return booleanize(condition); } // c ? true : x ---> !!c || x return make_node(AST_Binary, self, { operator: "||", - left: booleanize(self.condition), + left: booleanize(condition), right: self.alternative }); } if (is_false(self.consequent)) { if (is_true(self.alternative)) { // c ? false : true ---> !c - return booleanize(self.condition.negate(compressor)); + return booleanize(condition.negate(compressor)); } // c ? false : x ---> !c && x return make_node(AST_Binary, self, { operator: "&&", - left: booleanize(self.condition.negate(compressor)), + left: booleanize(condition.negate(compressor)), right: self.alternative }); } @@ -4724,7 +6161,7 @@ merge(Compressor.prototype, { // c ? x : true ---> !c || x return make_node(AST_Binary, self, { operator: "||", - left: booleanize(self.condition.negate(compressor)), + left: booleanize(condition.negate(compressor)), right: self.consequent }); } @@ -4732,7 +6169,7 @@ merge(Compressor.prototype, { // c ? x : false ---> !!c && x return make_node(AST_Binary, self, { operator: "&&", - left: booleanize(self.condition), + left: booleanize(condition), right: self.consequent }); } @@ -4740,7 +6177,7 @@ merge(Compressor.prototype, { return self; function booleanize(node) { - if (node.is_boolean()) return node; + if (node.is_boolean(compressor)) return node; // !!expression return make_node(AST_UnaryPrefix, node, { operator: "!", @@ -4783,38 +6220,59 @@ merge(Compressor.prototype, { } } } + + function pop_lhs(node) { + if (!(node instanceof AST_Sequence)) return node.right; + var exprs = node.expressions.slice(); + exprs.push(exprs.pop().right); + return make_sequence(node, exprs); + } + + function pop_seq(node) { + if (!(node instanceof AST_Sequence)) return make_node(AST_Number, node, { + value: 0 + }); + return make_sequence(node, node.expressions.slice(0, -1)); + } }); - OPT(AST_Boolean, function(self, compressor){ + OPT(AST_Boolean, function(self, compressor) { + if (!compressor.option("booleans")) return self; if (compressor.in_boolean_context()) return make_node(AST_Number, self, { value: +self.value }); - if (compressor.option("booleans")) { - var p = compressor.parent(); - if (p instanceof AST_Binary && (p.operator == "==" - || p.operator == "!=")) { - compressor.warn("Non-strict equality against boolean: {operator} {value} [{file}:{line},{col}]", { - operator : p.operator, - value : self.value, - file : p.start.file, - line : p.start.line, - col : p.start.col, - }); - return make_node(AST_Number, self, { - value: +self.value - }); - } - return make_node(AST_UnaryPrefix, self, { - operator: "!", - expression: make_node(AST_Number, self, { - value: 1 - self.value - }) + var p = compressor.parent(); + if (p instanceof AST_Binary && (p.operator == "==" || p.operator == "!=")) { + compressor.warn("Non-strict equality against boolean: {operator} {value} [{file}:{line},{col}]", { + operator : p.operator, + value : self.value, + file : p.start.file, + line : p.start.line, + col : p.start.col, + }); + return make_node(AST_Number, self, { + value: +self.value }); } - return self; + return make_node(AST_UnaryPrefix, self, { + operator: "!", + expression: make_node(AST_Number, self, { + value: 1 - self.value + }) + }); }); - OPT(AST_Sub, function(self, compressor){ + function safe_to_flatten(value, compressor) { + if (value instanceof AST_SymbolRef) { + value = value.fixed_value(); + } + if (!value) return false; + return !(value instanceof AST_Lambda) + || compressor.parent() instanceof AST_New + || !value.contains_this(); + } + + OPT(AST_Sub, function(self, compressor) { var expr = self.expression; var prop = self.property; if (compressor.option("properties")) { @@ -4841,6 +6299,39 @@ merge(Compressor.prototype, { } } } + var fn; + if (compressor.option("arguments") + && expr instanceof AST_SymbolRef + && expr.name == "arguments" + && expr.definition().orig.length == 1 + && (fn = expr.scope) instanceof AST_Lambda + && prop instanceof AST_Number) { + var index = prop.getValue(); + var argname = fn.argnames[index]; + if (argname && compressor.has_directive("use strict")) { + var def = argname.definition(); + if (!compressor.option("reduce_vars") || def.assignments || def.orig.length > 1) { + argname = null; + } + } else if (!argname && !compressor.option("keep_fargs") && index < fn.argnames.length + 5) { + while (index >= fn.argnames.length) { + argname = make_node(AST_SymbolFunarg, fn, { + name: fn.make_var_name("argument_" + fn.argnames.length), + scope: fn + }); + fn.argnames.push(argname); + fn.enclosed.push(fn.def_variable(argname)); + } + } + if (argname && find_if(function(node) { + return node.name === argname.name; + }, fn.argnames) === argname) { + var sym = make_node(AST_SymbolRef, self, argname); + sym.reference({}); + delete argname.__unused; + return sym; + } + } if (is_lhs(self, compressor.parent())) return self; if (key !== prop) { var sub = self.flatten_object(property, compressor); @@ -4853,7 +6344,8 @@ merge(Compressor.prototype, { && prop instanceof AST_Number && expr instanceof AST_Array) { var index = prop.getValue(); var elements = expr.elements; - if (index in elements) { + var retValue = elements[index]; + if (safe_to_flatten(retValue, compressor)) { var flatten = true; var values = []; for (var i = elements.length; --i > index;) { @@ -4863,7 +6355,6 @@ merge(Compressor.prototype, { if (flatten && value.has_side_effects(compressor)) flatten = false; } } - var retValue = elements[index]; retValue = retValue instanceof AST_Hole ? make_node(AST_Undefined, retValue) : retValue; if (!flatten) values.unshift(retValue); while (--i >= 0) { @@ -4892,7 +6383,7 @@ merge(Compressor.prototype, { return self; }); - AST_Lambda.DEFMETHOD("contains_this", function() { + AST_Scope.DEFMETHOD("contains_this", function() { var result; var self = this; self.walk(new TreeWalker(function(node) { @@ -4914,10 +6405,7 @@ merge(Compressor.prototype, { if (!all(props, function(prop) { return prop instanceof AST_ObjectKeyVal; })) break; - var value = prop.value; - if (value instanceof AST_Function - && !(compressor.parent() instanceof AST_New) - && value.contains_this()) break; + if (!safe_to_flatten(prop.value, compressor)) break; return make_node(AST_Sub, this, { expression: make_node(AST_Array, expr, { elements: props.map(function(prop) { @@ -4933,11 +6421,16 @@ merge(Compressor.prototype, { } }); - OPT(AST_Dot, function(self, compressor){ - var def = self.resolve_defines(compressor); - if (def) { - return def.optimize(compressor); + OPT(AST_Dot, function(self, compressor) { + if (self.property == "arguments" || self.property == "caller") { + compressor.warn("Function.protoype.{prop} not supported [{file}:{line},{col}]", { + prop: self.property, + file: self.start.file, + line: self.start.line, + col: self.start.col + }); } + if (is_lhs(self, compressor.parent())) return self; if (compressor.option("unsafe_proto") && self.expression instanceof AST_Dot && self.expression.property == "prototype") { @@ -4948,11 +6441,27 @@ merge(Compressor.prototype, { elements: [] }); break; + case "Function": + self.expression = make_node(AST_Function, self.expression, { + argnames: [], + body: [] + }); + break; + case "Number": + self.expression = make_node(AST_Number, self.expression, { + value: 0 + }); + break; case "Object": self.expression = make_node(AST_Object, self.expression, { properties: [] }); break; + case "RegExp": + self.expression = make_node(AST_RegExp, self.expression, { + value: /t/ + }); + break; case "String": self.expression = make_node(AST_String, self.expression, { value: "" @@ -4960,7 +6469,6 @@ merge(Compressor.prototype, { break; } } - if (is_lhs(self, compressor.parent())) return self; var sub = self.flatten_object(self.property, compressor); if (sub) return sub.optimize(compressor); var ev = self.evaluate(compressor); @@ -4971,32 +6479,19 @@ merge(Compressor.prototype, { return self; }); - function literals_in_boolean_context(self, compressor) { - if (compressor.in_boolean_context()) { - return best_of(compressor, self, make_sequence(self, [ - self, - make_node(AST_True, self) - ]).optimize(compressor)); - } - return self; - }; - OPT(AST_Array, literals_in_boolean_context); - OPT(AST_Object, literals_in_boolean_context); - OPT(AST_RegExp, literals_in_boolean_context); - - OPT(AST_Return, function(self, compressor){ + OPT(AST_Return, function(self, compressor) { if (self.value && is_undefined(self.value, compressor)) { self.value = null; } return self; }); - - OPT(AST_VarDef, function(self, compressor){ - var defines = compressor.option("global_defs"); - if (defines && HOP(defines, self.name.name)) { - compressor.warn('global_defs ' + self.name.name + ' redefined [{file}:{line},{col}]', self.start); - } - return self; +})(function(node, optimizer) { + node.DEFMETHOD("optimize", function(compressor) { + var self = this; + if (self._optimized) return self; + if (compressor.has_directive("use asm")) return self; + var opt = optimizer(self, compressor); + opt._optimized = true; + return opt; }); - -})(); +}); -- cgit v1.2.3