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enhance reduce_vars (#5164)
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- fix corner case in `join_vars`
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@alexlamsl
alexlamsl committed Nov 4, 2021
1 parent f9a4b36 commit 6e4aa03
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Showing 3 changed files with 98 additions and 13 deletions.
43 changes: 31 additions & 12 deletions lib/compress.js
View file
Original file line number Diff line number Diff line change
Expand Up @@ -389,7 +389,18 @@ merge(Compressor.prototype, {
}
var lhs = is_lhs(node, parent);
if (lhs) return lhs;
if (level == 0 && value && value.is_constant()) return;
if (parent instanceof AST_Array) return is_modified(compressor, tw, parent, parent, level + 1);
if (parent instanceof AST_Assign) switch (parent.operator) {
case "=":
return is_modified(compressor, tw, parent, value, level + 1, immutable, recursive);
case "&&=":
case "||=":
case "??=":
return is_modified(compressor, tw, parent, parent, level + 1);
default:
return;
}
if (parent instanceof AST_Binary) {
if (!lazy_op[parent.operator]) return;
return is_modified(compressor, tw, parent, parent, level + 1);
Expand Down Expand Up @@ -625,7 +636,7 @@ merge(Compressor.prototype, {
if (def.fixed === undefined) return declare || all(def.orig, function(sym) {
return !(sym instanceof AST_SymbolLet);
});
if (def.fixed === false) return false;
if (def.fixed === false || def.fixed === 0) return false;
var safe = tw.safe_ids[def.id];
if (def.safe_ids) {
def.safe_ids[def.id] = false;
Expand Down Expand Up @@ -973,7 +984,13 @@ merge(Compressor.prototype, {
}
var d = sym.definition();
d.assignments++;
if (fixed && !modified && !sym.in_arg && safe_to_assign(tw, d)) {
if (!fixed || sym.in_arg || !safe_to_assign(tw, d)) {
walk();
d.fixed = false;
} else if (modified) {
walk();
d.fixed = 0;
} else {
push_ref(d, sym);
mark(tw, d);
if (left instanceof AST_Destructured
Expand All @@ -984,9 +1001,6 @@ merge(Compressor.prototype, {
mark_escaped(tw, d, sym.scope, node, right, 0, 1);
sym.fixed = d.fixed = fixed;
sym.fixed.assigns = [ node ];
} else {
walk();
d.fixed = false;
}
});
}
Expand Down Expand Up @@ -1265,7 +1279,7 @@ merge(Compressor.prototype, {
if (!safe) return;
safe.assign = true;
});
if (d.fixed === false) {
if (d.fixed === false || d.fixed === 0) {
var redef = d.redefined();
if (redef && cross_scope(d.scope, this.scope)) redef.single_use = false;
} else if (d.fixed === undefined || !safe_to_read(tw, d)) {
Expand All @@ -1290,7 +1304,7 @@ merge(Compressor.prototype, {
if (d.single_use) {
d.single_use = "m";
} else {
d.fixed = false;
d.fixed = 0;
}
}
if (d.fixed && tw.loop_ids[d.id] !== tw.in_loop) d.cross_loop = true;
Expand Down Expand Up @@ -1475,9 +1489,14 @@ merge(Compressor.prototype, {

AST_Symbol.DEFMETHOD("fixed_value", function() {
var fixed = this.definition().fixed;
if (fixed) {
if (this.fixed) fixed = this.fixed;
return fixed instanceof AST_Node ? fixed : fixed();
}
fixed = fixed === 0 && this.fixed;
if (!fixed) return fixed;
if (this.fixed) fixed = this.fixed;
return fixed instanceof AST_Node ? fixed : fixed();
var value = fixed instanceof AST_Node ? fixed : fixed();
return value.is_constant() && value;
});

AST_SymbolRef.DEFMETHOD("is_immutable", function() {
Expand Down Expand Up @@ -3593,11 +3612,11 @@ merge(Compressor.prototype, {
if (!(node.left instanceof AST_PropAccess)) return;
var sym = node.left.expression;
if (!(sym instanceof AST_SymbolRef)) return;
if (!names[sym.name]) return;
if (!(sym.name in names)) return;
if (!node.right.is_constant_expression(scope)) return;
var prop = node.left.property;
if (prop instanceof AST_Node) {
if (try_join(prop)) prop = node.left.property = prop.right;
if (try_join(prop)) prop = node.left.property = prop.right.clone();
prop = prop.evaluate(compressor);
}
if (prop instanceof AST_Node) return;
Expand All @@ -3615,7 +3634,7 @@ merge(Compressor.prototype, {
if (!all(value.properties, diff)) return;
value.properties.push(make_node(AST_ObjectKeyVal, node, {
key: prop,
value: node.right
value: node.right,
}));
return true;
}
Expand Down
27 changes: 26 additions & 1 deletion test/compress/join_vars.js
View file
Original file line number Diff line number Diff line change
Expand Up @@ -507,7 +507,7 @@ chained_assignments: {
expect_stdout: "PASS"
}

folded_assignments: {
folded_assignments_1: {
options = {
evaluate: true,
join_vars: true,
Expand All @@ -527,6 +527,30 @@ folded_assignments: {
expect_stdout: "PASS 42"
}

folded_assignments_2: {
options = {
evaluate: true,
join_vars: true,
}
input: {
"use strict";
var a = {};
a[42] = "FAIL";
a[a.PASS = 42] = "PASS";
console.log(a[42], a.PASS);
}
expect: {
"use strict";
var a = {
42: "FAIL",
PASS: 42,
};
a[42] = "PASS";
console.log(a[42], a.PASS);
}
expect_stdout: "PASS 42"
}

inlined_assignments: {
options = {
join_vars: true,
Expand All @@ -550,6 +574,7 @@ typescript_enum: {
rename = true
options = {
assignments: true,
collapse_vars: true,
evaluate: true,
hoist_props: true,
inline: true,
Expand Down
41 changes: 41 additions & 0 deletions test/compress/reduce_vars.js
View file
Original file line number Diff line number Diff line change
Expand Up @@ -7320,6 +7320,46 @@ local_assignment_loop: {
expect_stdout: "PASS"
}

local_assignment_modified: {
options = {
evaluate: true,
reduce_vars: true,
side_effects: true,
toplevel: true,
}
input: {
var a;
(a = a || {}).p = 42;
console.log(a.p);
}
expect: {
var a;
(a = {}).p = 42;
console.log(a.p);
}
expect_stdout: "42"
}

local_definition_modified: {
options = {
evaluate: true,
reduce_vars: true,
side_effects: true,
toplevel: true,
}
input: {
var a = a || {};
a.p = 42;
console.log(a.p);
}
expect: {
var a = {};
a.p = 42;
console.log(a.p);
}
expect_stdout: "42"
}

issue_3957_1: {
options = {
evaluate: true,
Expand Down Expand Up @@ -7435,6 +7475,7 @@ issue_4030: {
collapse_vars: true,
evaluate: true,
reduce_vars: true,
side_effects: true,
toplevel: true,
unused: true,
}
Expand Down

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