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enhance side_effects (#3410)

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This commit is contained in:
Alex Lam S.L
2019-05-14 05:26:40 +08:00
committed by GitHub
parent 2e4fbdeb08
commit d538a73250
3 changed files with 62 additions and 11 deletions
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31
lib/compress.js
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@@ -347,6 +347,12 @@ merge(Compressor.prototype, {
}
}
function is_arguments(def) {
if (def.name != "arguments") return false;
var orig = def.orig;
return orig.length == 1 && orig[0] instanceof AST_SymbolFunarg;
}
(function(def) {
def(AST_Node, noop);
@@ -444,9 +450,8 @@ merge(Compressor.prototype, {
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;
def.fixed = make_node(AST_Undefined, orig);
if (is_arguments(def)) return false;
def.fixed = make_node(AST_Undefined, def.orig);
}
return true;
}
@@ -522,7 +527,9 @@ merge(Compressor.prototype, {
if (!(node instanceof AST_Sub)) return;
var expr = node.expression;
var prop = node.property;
if (expr instanceof AST_SymbolRef && expr.name == "arguments" && prop instanceof AST_Number) {
if (expr instanceof AST_SymbolRef
&& is_arguments(expr.definition())
&& prop instanceof AST_Number) {
expr.definition().reassigned = true;
}
}
@@ -791,7 +798,7 @@ merge(Compressor.prototype, {
});
def(AST_Unary, function(tw, descend) {
var node = this;
if (node.operator != "++" && node.operator != "--") return;
if (!unary_arithmetic[node.operator]) return;
var exp = node.expression;
if (!(exp instanceof AST_SymbolRef)) {
mark_assignment_to_arguments(exp);
@@ -1437,7 +1444,7 @@ merge(Compressor.prototype, {
extract_candidates(expr.expression);
expr.body.forEach(extract_candidates);
} else if (expr instanceof AST_Unary) {
if (expr.operator == "++" || expr.operator == "--") {
if (unary_arithmetic[expr.operator]) {
candidates.push(hit_stack.slice());
} else {
extract_candidates(expr.expression);
@@ -1507,9 +1514,9 @@ merge(Compressor.prototype, {
function mangleable_var(var_def) {
var value = var_def.value;
if (!(value instanceof AST_SymbolRef)) return;
if (value.name == "arguments") return;
var def = value.definition();
if (def.undeclared) return;
if (is_arguments(def)) return;
return value_def = def;
}
@@ -2313,6 +2320,7 @@ merge(Compressor.prototype, {
if (!is_strict(compressor)) return false;
if (is_undeclared_ref(this) && this.is_declared(compressor)) return false;
if (this.is_immutable()) return false;
if (is_arguments(this.definition())) return false;
var fixed = this.fixed_value();
if (!fixed) return true;
this._dot_throw = return_true;
@@ -2555,6 +2563,7 @@ merge(Compressor.prototype, {
});
var lazy_op = makePredicate("&& ||");
var unary_arithmetic = makePredicate("++ --");
var unary_side_effects = makePredicate("delete ++ --");
function is_lhs(node, parent) {
@@ -4412,8 +4421,9 @@ merge(Compressor.prototype, {
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);
if (compressor.option("side_effects")) {
if (self.init) self.init = self.init.drop_side_effect_free(compressor);
if (self.step) self.step = self.step.drop_side_effect_free(compressor);
}
if (self.condition) {
var cond = self.condition.evaluate(compressor);
@@ -6644,8 +6654,7 @@ merge(Compressor.prototype, {
var fn;
if (compressor.option("arguments")
&& expr instanceof AST_SymbolRef
&& expr.name == "arguments"
&& expr.definition().orig.length == 1
&& is_arguments(expr.definition())
&& prop instanceof AST_Number
&& (fn = expr.scope) === compressor.find_parent(AST_Lambda)) {
var index = prop.getValue();