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fix AST_Node.optimize() (#1602)

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Liberal use of `Compressor.transform()` and `AST_Node.optimize()` presents an issue for look-up operations like `TreeWalker.in_boolean_context()` and `TreeWalker.parent()`.

This is an incremental fix such that `AST_Node.optimize()` would now contain the correct stack information when called correctly.
This commit is contained in:
Alex Lam S.L
2017-03-15 18:44:13 +08:00
committed by GitHub
parent 381bd3836e
commit 8223b2e0db
3 changed files with 164 additions and 38 deletions
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69
lib/compress.js
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@@ -152,13 +152,14 @@ merge(Compressor.prototype, {
was_scope = true;
}
descend(node, this);
node = node.optimize(this);
if (was_scope && node instanceof AST_Scope) {
node.drop_unused(this);
descend(node, this);
descend(node, this);
var opt = node.optimize(this);
if (was_scope && opt instanceof AST_Scope) {
opt.drop_unused(this);
descend(opt, this);
}
node._squeezed = true;
return node;
if (opt === node) opt._squeezed = true;
return opt;
}
});
@@ -171,8 +172,7 @@ merge(Compressor.prototype, {
if (compressor.has_directive("use asm")) return self;
var opt = optimizer(self, compressor);
opt._optimized = true;
if (opt === self) return opt;
return opt.transform(compressor);
return opt;
});
};
@@ -914,7 +914,7 @@ merge(Compressor.prototype, {
if (stat instanceof AST_LoopControl) {
var lct = compressor.loopcontrol_target(stat.label);
if ((stat instanceof AST_Break
&& lct instanceof AST_BlockStatement
&& !(lct instanceof AST_IterationStatement)
&& loop_body(lct) === self) || (stat instanceof AST_Continue
&& loop_body(lct) === self)) {
if (stat.label) {
@@ -1646,8 +1646,8 @@ merge(Compressor.prototype, {
return thing && thing.aborts();
};
(function(def){
def(AST_Statement, function(){ return null });
def(AST_Jump, function(){ return this });
def(AST_Statement, return_null);
def(AST_Jump, return_this);
function block_aborts(){
var n = this.body.length;
return n > 0 && aborts(this.body[n - 1]);
@@ -2077,14 +2077,6 @@ merge(Compressor.prototype, {
// drop_side_effect_free()
// remove side-effect-free parts which only affects return value
(function(def){
function return_this() {
return this;
}
function return_null() {
return null;
}
// 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
@@ -2358,7 +2350,7 @@ merge(Compressor.prototype, {
extract_declarations_from_unreachable_code(compressor, self.alternative, a);
}
a.push(self.body);
return make_node(AST_BlockStatement, self, { body: a }).transform(compressor);
return make_node(AST_BlockStatement, self, { body: a }).optimize(compressor);
}
} else {
compressor.warn("Condition always false [{file}:{line},{col}]", self.condition.start);
@@ -2366,7 +2358,7 @@ merge(Compressor.prototype, {
var a = [];
extract_declarations_from_unreachable_code(compressor, self.body, a);
if (self.alternative) a.push(self.alternative);
return make_node(AST_BlockStatement, self, { body: a }).transform(compressor);
return make_node(AST_BlockStatement, self, { body: a }).optimize(compressor);
}
}
}
@@ -2385,8 +2377,8 @@ merge(Compressor.prototype, {
}
if (is_empty(self.body) && is_empty(self.alternative)) {
return make_node(AST_SimpleStatement, self.condition, {
body: self.condition
}).transform(compressor);
body: self.condition.clone()
}).optimize(compressor);
}
if (self.body instanceof AST_SimpleStatement
&& self.alternative instanceof AST_SimpleStatement) {
@@ -2396,7 +2388,7 @@ merge(Compressor.prototype, {
consequent : statement_to_expression(self.body),
alternative : statement_to_expression(self.alternative)
})
}).transform(compressor);
}).optimize(compressor);
}
if (is_empty(self.alternative) && self.body instanceof AST_SimpleStatement) {
if (self_condition_length === negated_length && !negated_is_best
@@ -2412,14 +2404,14 @@ merge(Compressor.prototype, {
left : negated,
right : statement_to_expression(self.body)
})
}).transform(compressor);
}).optimize(compressor);
return make_node(AST_SimpleStatement, self, {
body: make_node(AST_Binary, self, {
operator : "&&",
left : self.condition,
right : statement_to_expression(self.body)
})
}).transform(compressor);
}).optimize(compressor);
}
if (self.body instanceof AST_EmptyStatement
&& self.alternative
@@ -2430,7 +2422,7 @@ merge(Compressor.prototype, {
left : self.condition,
right : statement_to_expression(self.alternative)
})
}).transform(compressor);
}).optimize(compressor);
}
if (self.body instanceof AST_Exit
&& self.alternative instanceof AST_Exit
@@ -2440,18 +2432,21 @@ merge(Compressor.prototype, {
condition : self.condition,
consequent : self.body.value || make_node(AST_Undefined, self.body),
alternative : self.alternative.value || make_node(AST_Undefined, self.alternative)
})
}).transform(compressor);
}).transform(compressor)
}).optimize(compressor);
}
if (self.body instanceof AST_If
&& !self.body.alternative
&& !self.alternative) {
self.condition = make_node(AST_Binary, self.condition, {
operator: "&&",
left: self.condition,
right: self.body.condition
}).transform(compressor);
self.body = self.body.body;
self = make_node(AST_If, self, {
condition: make_node(AST_Binary, self.condition, {
operator: "&&",
left: self.condition,
right: self.body.condition
}),
body: self.body.body,
alternative: null
});
}
if (aborts(self.body)) {
if (self.alternative) {
@@ -2459,7 +2454,7 @@ merge(Compressor.prototype, {
self.alternative = null;
return make_node(AST_BlockStatement, self, {
body: [ self, alt ]
}).transform(compressor);
}).optimize(compressor);
}
}
if (aborts(self.alternative)) {
@@ -2469,7 +2464,7 @@ merge(Compressor.prototype, {
self.alternative = null;
return make_node(AST_BlockStatement, self, {
body: [ self, body ]
}).transform(compressor);
}).optimize(compressor);
}
return self;
});