augment evaluate to extract within objects (#1425)
- gated by `unsafe` - replaces previous optimisation specific to String.length - "123"[0] => 1 - [1, 2, 3][0] => 1 - [1, 2, 3].length => 3 - does not apply to objects with overridden prototype functions
This commit is contained in:
Alex Lam S.L
committed by
Richard van Velzen
Richard van Velzen
parent
48284844a4
commit
0d7d4918eb
@@ -152,6 +152,12 @@ merge(Compressor.prototype, {
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AST_Node.DEFMETHOD("clear_opt_flags", function(){
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this.walk(new TreeWalker(function(node){
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if (node instanceof AST_SymbolRef) {
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var d = node.definition();
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if (d && d.init) {
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delete d.init._evaluated;
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}
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}
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if (!(node instanceof AST_Directive || node instanceof AST_Constant)) {
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node._squeezed = false;
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node._optimized = false;
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@@ -992,13 +998,20 @@ merge(Compressor.prototype, {
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// constant; otherwise it's the original or a replacement node.
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AST_Node.DEFMETHOD("evaluate", function(compressor){
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if (!compressor.option("evaluate")) return [ this ];
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var val;
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try {
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var val = this._eval(compressor);
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return [ best_of(make_node_from_constant(compressor, val, this), this), val ];
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val = this._eval(compressor);
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} catch(ex) {
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if (ex !== def) throw ex;
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return [ this ];
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}
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var node;
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try {
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node = make_node_from_constant(compressor, val, this);
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} catch(ex) {
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return [ this ];
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}
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return [ best_of(node, this), val ];
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});
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AST_Node.DEFMETHOD("is_constant", function(compressor){
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// Accomodate when compress option evaluate=false
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@@ -1047,6 +1060,32 @@ merge(Compressor.prototype, {
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def(AST_Constant, function(){
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return this.getValue();
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});
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def(AST_Array, function(compressor){
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if (compressor.option("unsafe")) {
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return this.elements.map(function(element) {
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return ev(element, compressor);
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});
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}
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throw def;
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});
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def(AST_Object, function(compressor){
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if (compressor.option("unsafe")) {
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var val = {};
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for (var i = 0, len = this.properties.length; i < len; i++) {
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var prop = this.properties[i];
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var key = prop.key;
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if (key instanceof AST_Node) {
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key = ev(key, compressor);
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}
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if (typeof Object.prototype[key] === 'function') {
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throw def;
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}
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val[key] = ev(prop.value, compressor);
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}
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return val;
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}
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throw def;
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});
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def(AST_UnaryPrefix, function(compressor){
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var e = this.expression;
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switch (this.operator) {
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@@ -1114,6 +1153,12 @@ merge(Compressor.prototype, {
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try {
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var d = this.definition();
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if (d && (d.constant || compressor.option("reduce_vars") && !d.modified) && d.init) {
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if (compressor.option("unsafe")) {
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if (!HOP(d.init, '_evaluated')) {
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d.init._evaluated = ev(d.init, compressor);
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}
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return d.init._evaluated;
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}
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return ev(d.init, compressor);
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}
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} finally {
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@@ -1121,11 +1166,16 @@ merge(Compressor.prototype, {
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}
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throw def;
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});
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def(AST_Dot, function(compressor){
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if (compressor.option("unsafe") && this.property == "length") {
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var str = ev(this.expression, compressor);
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if (typeof str == "string")
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return str.length;
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def(AST_PropAccess, function(compressor){
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if (compressor.option("unsafe")) {
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var key = this.property;
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if (key instanceof AST_Node) {
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key = ev(key, compressor);
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}
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var val = ev(this.expression, compressor);
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if (val && HOP(val, key)) {
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return val[key];
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}
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}
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throw def;
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});
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@@ -2890,7 +2940,7 @@ merge(Compressor.prototype, {
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});
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}
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}
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return self;
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return self.evaluate(compressor)[0];
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});
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OPT(AST_Dot, function(self, compressor){
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17
lib/scope.js
17
lib/scope.js
@@ -184,6 +184,17 @@ AST_Toplevel.DEFMETHOD("figure_out_scope", function(options){
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var func = null;
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var globals = self.globals = new Dictionary();
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var tw = new TreeWalker(function(node, descend){
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function isModified(node, level) {
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var parent = tw.parent(level);
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if (parent instanceof AST_Unary && (parent.operator === "++" || parent.operator === "--")
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|| parent instanceof AST_Assign && parent.left === node
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|| parent instanceof AST_Call && parent.expression === node) {
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return true;
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} else if (parent instanceof AST_PropAccess && parent.expression === node) {
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return isModified(parent, level + 1);
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}
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}
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if (node instanceof AST_Lambda) {
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var prev_func = func;
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func = node;
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@@ -197,8 +208,7 @@ AST_Toplevel.DEFMETHOD("figure_out_scope", function(options){
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}
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if (node instanceof AST_SymbolRef) {
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var name = node.name;
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var parent = tw.parent();
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if (name == "eval" && parent instanceof AST_Call) {
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if (name == "eval" && tw.parent() instanceof AST_Call) {
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for (var s = node.scope; s && !s.uses_eval; s = s.parent_scope) {
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s.uses_eval = true;
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}
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@@ -220,8 +230,7 @@ AST_Toplevel.DEFMETHOD("figure_out_scope", function(options){
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sym = g;
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}
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node.thedef = sym;
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if (parent instanceof AST_Unary && (parent.operator === "++" || parent.operator === "--")
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|| parent instanceof AST_Assign && parent.left === node) {
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if (isModified(node, 0)) {
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sym.modified = true;
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}
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node.reference();
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