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enhance collapse_vars & reduce_vars (#5275)

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fixes #5276
This commit is contained in:
Alex Lam S.L
2022-01-07 21:26:49 +00:00
committed by GitHub
parent be8c75bae1
commit b0df5d7b55
2 changed files with 109 additions and 24 deletions
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56
lib/compress.js
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@@ -674,6 +674,16 @@ Compressor.prototype.compress = function(node) {
return node;
}
function replace_ref(ref, fixed) {
return function() {
var node = make_ref(ref, fixed);
var def = ref.definition();
def.references.push(node);
def.replaced++;
return node;
};
}
function ref_once(compressor, def) {
return compressor.option("unused")
&& !def.scope.pinned()
@@ -954,6 +964,7 @@ Compressor.prototype.compress = function(node) {
};
left.fixed.assigns = !fixed || !fixed.assigns ? [] : fixed.assigns.slice();
left.fixed.assigns.push(node);
left.fixed.to_binary = replace_ref(left, fixed);
} else {
left.walk(tw);
ld.fixed = false;
@@ -1397,7 +1408,7 @@ Compressor.prototype.compress = function(node) {
operator: node.operator.slice(0, -1),
left: make_node(AST_UnaryPrefix, node, {
operator: "+",
expression: make_ref(exp, fixed)
expression: make_ref(exp, fixed),
}),
right: make_node(AST_Number, node, { value: 1 }),
});
@@ -1414,6 +1425,7 @@ Compressor.prototype.compress = function(node) {
});
};
exp.fixed.assigns = fixed && fixed.assigns;
exp.fixed.to_prefix = replace_ref(exp, d.fixed);
}
} else {
exp.walk(tw);
@@ -1960,6 +1972,7 @@ Compressor.prototype.compress = function(node) {
col: node.start.col,
});
can_replace = false;
lvalues = get_lvalues(lhs);
node.right.transform(scanner);
clear_write_only(candidate);
var folded;
@@ -1967,10 +1980,9 @@ Compressor.prototype.compress = function(node) {
folded = candidate;
} else {
abort = true;
lhs.definition().fixed = false;
folded = make_node(AST_Binary, candidate, {
operator: compound,
left: lhs,
left: lhs.fixed ? lhs.fixed.to_binary() : lhs,
right: rvalue,
});
}
@@ -2026,10 +2038,10 @@ Compressor.prototype.compress = function(node) {
alternative: node,
}),
});
if (candidate instanceof AST_UnaryPostfix) {
if (lhs instanceof AST_SymbolRef) lhs.definition().fixed = false;
return make_node(AST_UnaryPrefix, candidate, candidate);
}
if (candidate instanceof AST_UnaryPostfix) return make_node(AST_UnaryPrefix, candidate, {
operator: candidate.operator,
expression: lhs.fixed ? lhs.fixed.to_prefix() : lhs,
});
if (candidate instanceof AST_VarDef) {
var def = candidate.name.definition();
if (def.references.length - def.replaced == 1 && !compressor.exposed(def)) {
@@ -3086,16 +3098,13 @@ Compressor.prototype.compress = function(node) {
var value = rvalue === rhs_value ? null : make_sequence(rhs_value, rhs_value.expressions.slice(0, -1));
var index = expr.name_index;
if (index >= 0) {
var argname = scope.argnames[index];
var args, argname = scope.argnames[index];
if (argname instanceof AST_DefaultValue) {
scope.argnames[index] = argname = argname.clone();
argname.value = value || make_node(AST_Number, argname, { value: 0 });
argname.name.definition().fixed = false;
} else {
var args = compressor.parent().args;
if (args[index]) {
args[index] = value || make_node(AST_Number, args[index], { value: 0 });
argname.definition().fixed = false;
}
} else if ((args = compressor.parent().args)[index]) {
scope.argnames[index] = argname.clone();
args[index] = value || make_node(AST_Number, args[index], { value: 0 });
}
return;
}
@@ -6677,7 +6686,7 @@ Compressor.prototype.compress = function(node) {
&& indexOf_assign(node.expression.definition(), node) < 0) {
return make_node(AST_UnaryPrefix, node, {
operator: "+",
expression: node.expression
expression: node.expression,
});
}
}
@@ -11946,22 +11955,29 @@ Compressor.prototype.compress = function(node) {
}
if (compressor.option("assignments")) {
if (self.operator == "=" && self.left instanceof AST_SymbolRef && self.right instanceof AST_Binary) {
var ref;
// x = expr1 OP expr2
if (self.right.left instanceof AST_SymbolRef
&& self.right.left.name == self.left.name
if ((ref = self.right.left) instanceof AST_SymbolRef
&& ref.name == self.left.name
&& ASSIGN_OPS[self.right.operator]) {
// x = x - 2 ---> x -= 2
if (self.left.fixed) self.left.fixed.to_binary = function() {
return ref;
};
return make_node(AST_Assign, self, {
operator: self.right.operator + "=",
left: self.left,
right: self.right.right,
});
}
if (self.right.right instanceof AST_SymbolRef
&& self.right.right.name == self.left.name
if ((ref = self.right.right) instanceof AST_SymbolRef
&& ref.name == self.left.name
&& ASSIGN_OPS_COMMUTATIVE[self.right.operator]
&& !self.right.left.has_side_effects(compressor)) {
// x = 2 & x ---> x &= 2
if (self.left.fixed) self.left.fixed.to_binary = function() {
return ref;
};
return make_node(AST_Assign, self, {
operator: self.right.operator + "=",
left: self.left,