JoBoEVD/UglifyJS
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

reduce this within functions (#2421)

Browse Source 
- only replace same-scope usages
- augment `test/ufuzz.js` to test for `this`


fixes #2420
This commit is contained in:
Alex Lam S.L
2017-11-04 00:31:37 +08:00
committed by GitHub
parent a48f87abf2
commit c8b6f4733d
3 changed files with 129 additions and 31 deletions
Download Patch File Download Diff File Expand all files Collapse all files

75
lib/compress.js
View File

@@ -285,7 +285,7 @@ merge(Compressor.prototype, {
self.transform(tt);
});
AST_Node.DEFMETHOD("reset_opt_flags", function(compressor) {
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
@@ -564,7 +564,10 @@ merge(Compressor.prototype, {
}
function is_immutable(value) {
return value && (value.is_constant() || value instanceof AST_Lambda);
if (!value) return false;
return value.is_constant()
|| value instanceof AST_Lambda
|| value instanceof AST_This;
}
function read_property(obj, key) {
@@ -4211,39 +4214,49 @@ merge(Compressor.prototype, {
var value = fixed.optimize(compressor);
return value === fixed ? fixed.clone(true) : value;
}
if (compressor.option("evaluate") && fixed) {
if (d.should_replace === undefined) {
var init = fixed.evaluate(compressor);
if (init !== fixed && (compressor.option("unsafe_regexp") || !(init instanceof RegExp))) {
init = make_node_from_constant(init, fixed);
var value_length = init.optimize(compressor).print_to_string().length;
var fn;
if (has_symbol_ref(fixed)) {
fn = function() {
var result = init.optimize(compressor);
return result === init ? result.clone(true) : result;
};
} else {
value_length = Math.min(value_length, fixed.print_to_string().length);
fn = function() {
var result = best_of_expression(init.optimize(compressor), fixed);
return result === init || result === fixed ? result.clone(true) : result;
};
}
var name_length = d.name.length;
var overhead = 0;
if (compressor.option("unused") && !compressor.exposed(d)) {
overhead = (name_length + 2 + value_length) / d.references.length;
}
d.should_replace = value_length <= name_length + overhead ? fn : false;
} else {
d.should_replace = false;
if (fixed && d.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;
})) {
init = fixed;
}
} else {
var ev = fixed.evaluate(compressor);
if (ev !== fixed && (compressor.option("unsafe_regexp") || !(ev instanceof RegExp))) {
init = make_node_from_constant(ev, fixed);
}
}
if (d.should_replace) {
return d.should_replace();
if (init) {
var value_length = init.optimize(compressor).print_to_string().length;
var fn;
if (has_symbol_ref(fixed)) {
fn = function() {
var result = init.optimize(compressor);
return result === init ? result.clone(true) : result;
};
} else {
value_length = Math.min(value_length, fixed.print_to_string().length);
fn = function() {
var result = best_of_expression(init.optimize(compressor), fixed);
return result === init || result === fixed ? result.clone(true) : result;
};
}
var name_length = d.name.length;
var overhead = 0;
if (compressor.option("unused") && !compressor.exposed(d)) {
overhead = (name_length + 2 + value_length) / d.references.length;
}
d.should_replace = value_length <= name_length + overhead ? fn : false;
} else {
d.should_replace = false;
}
}
if (d.should_replace) {
return d.should_replace();
}
}
return self;