Skip to content

Commit

Permalink
enhance unsafe (#3382)
Browse files Browse the repository at this point in the history
  • Loading branch information
@alexlamsl
alexlamsl committed Apr 24, 2019
1 parent c215706 commit c56d89f
Show file tree
Hide file tree
Showing 2 changed files with 86 additions and 34 deletions.
116 changes: 84 additions & 32 deletions lib/compress.js
View file
Expand Up @@ -2532,13 +2532,30 @@ merge(Compressor.prototype, {
return this.operator == "+" &&
(this.left.is_string(compressor) || this.right.is_string(compressor));
});
var fn = makePredicate([
"charAt",
"substr",
"substring",
"toLowerCase",
"toString",
"toUpperCase",
"trim",
]);
def(AST_Call, function(compressor) {
if (!compressor.option("unsafe")) return false;
var exp = this.expression;
return exp instanceof AST_Dot && fn[exp.property];
});
def(AST_Conditional, function(compressor) {
return this.consequent.is_string(compressor) && this.alternative.is_string(compressor);
});
def(AST_Sequence, function(compressor) {
return this.tail_node().is_string(compressor);
});
def(AST_String, return_true);
def(AST_Sub, function(compressor) {
return this.expression.is_string(compressor) && this.property instanceof AST_Number;
});
def(AST_SymbolRef, function(compressor) {
var fixed = this.fixed_value();
if (!fixed) return false;
Expand Down Expand Up @@ -3127,25 +3144,31 @@ merge(Compressor.prototype, {
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;
AST_Call.DEFMETHOD("is_call_pure", function(compressor) {
if (!compressor.option("unsafe")) return false;
var dot = this.expression;
if (!(dot instanceof AST_Dot)) return false;
var exp = dot.expression;
var map;
if (expr instanceof AST_Array) {
var prop = dot.property;
if (exp instanceof AST_Array) {
map = native_fns.Array;
} else if (expr.is_boolean(compressor)) {
} else if (exp.is_boolean(compressor)) {
map = native_fns.Boolean;
} else if (expr.is_number(compressor)) {
} else if (exp.is_number(compressor)) {
map = native_fns.Number;
} else if (expr instanceof AST_RegExp) {
} else if (exp instanceof AST_RegExp) {
map = native_fns.RegExp;
} else if (expr.is_string(compressor)) {
if (this.property == "replace") return false;
} else if (exp.is_string(compressor)) {
map = native_fns.String;
} else if (!this.may_throw_on_access(compressor)) {
if (prop == "replace") {
var arg = this.args[1];
if (arg && !arg.is_string(compressor)) return false;
}
} else if (!dot.may_throw_on_access(compressor)) {
map = native_fns.Object;
}
return map && map[this.property];
return map && map[prop];
});

// determine if expression has side effects
Expand All @@ -3170,8 +3193,7 @@ merge(Compressor.prototype, {
});
def(AST_Call, function(compressor) {
if (!this.is_expr_pure(compressor)
&& (!this.expression.is_call_pure(compressor)
|| this.expression.has_side_effects(compressor))) {
&& (!this.is_call_pure(compressor) || this.expression.has_side_effects(compressor))) {
return true;
}
return any(this.args, compressor);
Expand Down Expand Up @@ -4162,16 +4184,15 @@ merge(Compressor.prototype, {
});
def(AST_Call, function(compressor, first_in_statement) {
if (!this.is_expr_pure(compressor)) {
if (this.expression.is_call_pure(compressor)) {
var exp = this.expression;
if (this.is_call_pure(compressor)) {
var exprs = this.args.slice();
exprs.unshift(this.expression.expression);
exprs.unshift(exp.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)) {
if (exp instanceof AST_Function && (!exp.name || !exp.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) {
Expand Down Expand Up @@ -4963,15 +4984,21 @@ merge(Compressor.prototype, {
}
break;
case "charAt":
if (exp.expression.is_string(compressor)) {
var arg = self.args[0];
var index = arg ? arg.evaluate(compressor) : 0;
if (index !== arg) {
return make_node(AST_Sub, exp, {
expression: exp.expression,
property: make_node_from_constant(index | 0, arg || exp)
}).optimize(compressor);
}
if (self.args.length < 2) {
var node = make_node(AST_Sub, self, {
expression: exp.expression,
property: self.args.length ? make_node(AST_Binary, self.args[0], {
operator: "|",
left: make_node(AST_Number, self, {
value: 0
}),
right: self.args[0]
}) : make_node(AST_Number, self, {
value: 0
})
});
node.is_string = return_true;
return node.optimize(compressor);
}
break;
case "apply":
Expand Down Expand Up @@ -5610,7 +5637,8 @@ merge(Compressor.prototype, {
}
break;
}
if (compressor.option("booleans") && self.operator == "+" && compressor.in_boolean_context()) {
if (compressor.option("booleans") && compressor.in_boolean_context()) switch (self.operator) {
case "+":
var ll = self.left.evaluate(compressor);
var rr = self.right.evaluate(compressor);
if (ll && typeof ll == "string") {
Expand All @@ -5627,6 +5655,20 @@ merge(Compressor.prototype, {
make_node(AST_True, self)
]).optimize(compressor);
}
break;
case "==":
if (self.left instanceof AST_String && self.left.getValue() == "" && self.right.is_string(compressor)) {
return make_node(AST_UnaryPrefix, self, {
operator: "!",
expression: self.right
}).optimize(compressor);
}
break;
case "!=":
if (self.left instanceof AST_String && self.left.getValue() == "" && self.right.is_string(compressor)) {
return self.right.optimize(compressor);
}
break;
}
if (compressor.option("comparisons") && self.is_boolean(compressor)) {
if (!(compressor.parent() instanceof AST_Binary)
Expand All @@ -5646,20 +5688,20 @@ merge(Compressor.prototype, {
if (self.right instanceof AST_String
&& self.right.getValue() == ""
&& self.left.is_string(compressor)) {
return self.left;
return self.left.optimize(compressor);
}
if (self.left instanceof AST_String
&& self.left.getValue() == ""
&& self.right.is_string(compressor)) {
return self.right;
return self.right.optimize(compressor);
}
if (self.left instanceof AST_Binary
&& self.left.operator == "+"
&& self.left.left instanceof AST_String
&& self.left.left.getValue() == ""
&& self.right.is_string(compressor)) {
self.left = self.left.right;
return self.transform(compressor);
return self.optimize(compressor);
}
}
if (compressor.option("evaluate")) {
Expand Down Expand Up @@ -5918,6 +5960,16 @@ merge(Compressor.prototype, {
&& self.right instanceof AST_Call
&& self.right.expression instanceof AST_Dot
&& indexFns[self.right.expression.property]) {
if (compressor.option("booleans")
&& (self.operator == "==" || self.operator == "!=")
&& self.left instanceof AST_Number
&& self.left.getValue() == 0
&& compressor.in_boolean_context()) {
return (self.operator == "==" ? make_node(AST_UnaryPrefix, self, {
operator: "!",
expression: self.right
}) : self.right).optimize(compressor);
}
if (compressor.option("comparisons") && is_indexOf_match_pattern()) {
var node = make_node(AST_UnaryPrefix, self, {
operator: "!",
Expand Down Expand Up @@ -6229,7 +6281,7 @@ merge(Compressor.prototype, {
if (parent instanceof AST_Exit) {
if (in_try(level, parent)) break;
if (is_reachable(def.scope, [ def ])) break;
if (self.operator == "=") return self.right;
if (self.operator == "=") return self.right.optimize(compressor);
def.fixed = false;
return make_node(AST_Binary, self, {
operator: self.operator.slice(0, -1),
Expand Down
4 changes: 2 additions & 2 deletions test/compress/evaluate.js
View file
Expand Up @@ -820,8 +820,8 @@ unsafe_charAt_noop: {
}
expect: {
console.log(
s.charAt(0),
"string".charAt(x),
s[0],
"string"[0 | x],
(typeof x)[0]
);
}
Expand Down

0 comments on commit c56d89f

Please sign in to comment.