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improve synergy between collapse_vars & unused (#2521)

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This commit is contained in:
Alex Lam S.L
2017-11-28 14:02:39 +08:00
committed by GitHub
parent ecc9f6b770
commit 32def5ebf5
4 changed files with 48 additions and 49 deletions
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44
lib/compress.js
View File

@@ -800,14 +800,6 @@ merge(Compressor.prototype, {
|| compressor.option("unsafe") && global_names(this.name);
});
function drop_decl(def) {
def.eliminated++;
if (def.orig.length == def.eliminated) {
def.scope.functions.del(def.name);
def.scope.variables.del(def.name);
}
}
function is_identifier_atom(node) {
return node instanceof AST_Infinity
|| node instanceof AST_NaN
@@ -1138,7 +1130,6 @@ merge(Compressor.prototype, {
if (node === expr || node.body === expr) {
found = true;
if (node instanceof AST_VarDef) {
drop_decl(node.name.definition());
node.value = null;
return node;
}
@@ -2484,7 +2475,7 @@ merge(Compressor.prototype, {
var def = node.name.definition();
if (!(def.id in in_use_ids)) {
compressor[node.name.unreferenced() ? "warn" : "info"]("Dropping unused function {name} [{file}:{line},{col}]", template(node.name));
drop_decl(def);
def.eliminated++;
return make_node(AST_EmptyStatement, node);
}
return node;
@@ -2503,10 +2494,17 @@ merge(Compressor.prototype, {
if (!drop_vars || sym.id in in_use_ids) {
if (def.name instanceof AST_SymbolVar) {
var var_defs = var_defs_by_id.get(sym.id);
if (var_defs.length > 1 && !def.value) {
if (var_defs.length > 1 && (!def.value || sym.orig.indexOf(def.name) > sym.eliminated)) {
compressor.warn("Dropping duplicated definition of variable {name} [{file}:{line},{col}]", template(def.name));
if (def.value) {
merge_sequence(side_effects, make_node(AST_Assign, def, {
operator: "=",
left: make_node(AST_SymbolRef, def.name, def.name),
right: def.value
}));
}
remove(var_defs, def);
drop_decl(sym);
sym.eliminated++;
return;
}
}
@@ -2539,25 +2537,9 @@ merge(Compressor.prototype, {
} else {
compressor[def.name.unreferenced() ? "warn" : "info"]("Dropping unused variable {name} [{file}:{line},{col}]", template(def.name));
}
drop_decl(sym);
sym.eliminated++;
}
});
if (head.length == 0 && tail.length == 1 && tail[0].name instanceof AST_SymbolVar) {
var var_defs = var_defs_by_id.get(tail[0].name.definition().id);
if (var_defs.length > 1) {
var def = tail.pop();
compressor.warn("Converting duplicated definition of variable {name} to assignment [{file}:{line},{col}]", template(def.name));
remove(var_defs, def);
side_effects.unshift(make_node(AST_Assign, def, {
operator: "=",
left: make_node(AST_SymbolRef, def.name, def.name),
right: def.value
}));
def = def.name.definition();
drop_decl(def);
def.replaced--;
}
}
if (head.length > 0 || tail.length > 0) {
node.definitions = head.concat(tail);
body.push(node);
@@ -3385,7 +3367,9 @@ merge(Compressor.prototype, {
}));
if (reduce_vars) name.definition().fixed = false;
}
drop_decl(def.name.definition());
def = def.name.definition();
def.eliminated++;
def.replaced--;
return a;
}, []);
if (assignments.length == 0) return null;

47
test/compress/collapse_vars.js
View File

@@ -2013,7 +2013,8 @@ chained_3: {
}
expect: {
console.log(function(a, b) {
var c = 1, c = b;
var c = 1;
c = b;
b++;
return c;
}(0, 2));
@@ -2081,7 +2082,7 @@ inner_lvalues: {
expect_stdout: true
}
double_def: {
double_def_1: {
options = {
collapse_vars: true,
unused: true,
@@ -2091,8 +2092,23 @@ double_def: {
a();
}
expect: {
var a = x;
(a = a && y)();
var a;
(a = (a = x) && y)();
}
}
double_def_2: {
options = {
collapse_vars: true,
toplevel: true,
unused: true,
}
input: {
var a = x, a = a && y;
a();
}
expect: {
(x && y)();
}
}
@@ -2201,7 +2217,7 @@ lvalues_def: {
}
expect: {
var a = 0, b = 1;
var a = b++, b = +void 0;
a = b++, b = +void 0;
a && a[a++];
console.log(a, b);
}
@@ -3074,10 +3090,9 @@ issue_2437: {
var result = !!req.onreadystatechange;
Object.defineProperty(XMLHttpRequest.prototype, 'onreadystatechange', xhrDesc || {});
return result;
}
else {
} else {
var req = new XMLHttpRequest();
var detectFunc = function () { };
var detectFunc = function () {};
req.onreadystatechange = detectFunc;
var result = req[SYMBOL_FAKE_ONREADYSTATECHANGE_1] === detectFunc;
req.onreadystatechange = null;
@@ -3093,9 +3108,9 @@ issue_2437: {
return Object.defineProperty(XMLHttpRequest.prototype, "onreadystatechange", xhrDesc || {}),
result;
}
var req = new XMLHttpRequest(), detectFunc = function() {};
req.onreadystatechange = detectFunc,
result = req[SYMBOL_FAKE_ONREADYSTATECHANGE_1] === detectFunc,
var req, detectFunc = function() {};
(req = new XMLHttpRequest()).onreadystatechange = detectFunc;
result = req[SYMBOL_FAKE_ONREADYSTATECHANGE_1] === detectFunc;
req.onreadystatechange = null;
}();
}
@@ -3609,15 +3624,15 @@ issue_2497: {
expect: {
function sample() {
if (true)
for (i = 0; i < 1; ++i)
for (k = 0; k < 1; ++k) {
for (var i = 0; i < 1; ++i)
for (var k = 0; k < 1; ++k) {
value = 1;
value = value ? value + 1 : 0;
}
else
for (var i = 0; i < 1; ++i)
for (var k = 0; k < 1; ++k)
var value=1;
for (i = 0; i < 1; ++i)
for (k = 0; k < 1; ++k)
var value = 1;
}
}
}

2
test/compress/drop-unused.js
View File

@@ -1294,8 +1294,8 @@ issue_2288: {
expect: {
function foo(o) {
o.a;
for (i = 0; i < 0; i++);
for (var i = 0; i < 0; i++);
for (i = 0; i < 0; i++);
}
}
}

4
test/compress/reduce_vars.js
View File

@@ -972,8 +972,8 @@ inner_var_for_2: {
}
expect: {
!function() {
a = 1;
for (var b = 1; --b;) var a = 2;
var a = 1;
for (var b = 1; --b;) a = 2;
console.log(a);
}();
}