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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
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@@ -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;