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fix corner case in loops & unused (#4356)

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fixes #4355
This commit is contained in:
Alex Lam S.L
2020-12-10 07:45:39 +00:00
committed by GitHub
parent 046bbde9d4
commit a59593cac8
3 changed files with 79 additions and 22 deletions
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37
lib/compress.js
View File

@@ -4542,7 +4542,7 @@ merge(Compressor.prototype, {
var def = node.definition();
if (member(def.scope, scopes)) return true;
if (scope && !def.redefined()) {
var scope_def = scope.find_variable(node);
var scope_def = scope.find_variable(node.name);
if (def.undeclared ? !scope_def : scope_def === def) {
result = "f";
return true;
@@ -4842,7 +4842,9 @@ merge(Compressor.prototype, {
if (!(ref instanceof AST_SymbolRef)) return;
var def = ref.definition();
var ldef = node.variables.get(ref.name);
if (ldef && (ldef === def || def.undeclared || node.parent_scope.find_variable(ref) === def)) {
if (ldef && (ldef === def
|| def.undeclared
|| node.parent_scope.find_variable(ref.name) === def)) {
references[def.id] = false;
references[ldef.id] = false;
} else {
@@ -5468,7 +5470,7 @@ merge(Compressor.prototype, {
}) : def.value === def.name.fixed_value())
&& (!def.value.name || (old_def = def.value.name.definition()).assignments == 0
&& (old_def.name == def.name.name || all(old_def.references, function(ref) {
return ref.scope.find_variable(def.name) === def.name.definition();
return ref.scope.find_variable(def.name.name) === def.name.definition();
})))
&& can_declare_defun()
&& can_rename(def.value, def.name.name)) {
@@ -5759,6 +5761,33 @@ merge(Compressor.prototype, {
if (init instanceof AST_SymbolRef) return init;
}
function find_variable(name) {
var level = 0;
var scope = self;
while (true) {
var in_arg = false;
do {
var parent = compressor.parent(level++);
if (parent instanceof AST_DestructuredKeyVal && parent.key === scope) {
var fn = compressor.parent(level + 1);
if (fn instanceof AST_Lambda) {
in_arg = fn.argnames.indexOf(compressor.parent(level)) >= 0;
level += 2;
scope = fn;
break;
}
}
if (!parent) return;
scope = parent;
} while (!(scope instanceof AST_BlockScope));
var def = scope.variables.get(name);
if (!def) continue;
if (!in_arg) return def;
var sym = def.orig[0];
if (sym instanceof AST_SymbolFunarg || sym instanceof AST_SymbolLambda) return def;
}
}
function scan_ref_scoped(node, descend, init) {
if (node instanceof AST_Assign && node.left instanceof AST_SymbolRef) {
var def = node.left.definition();
@@ -5807,7 +5836,7 @@ merge(Compressor.prototype, {
if (!sym) return;
var def = sym.definition();
if (def.scope !== self) {
var d = self.find_variable(sym);
var d = find_variable(sym.name);
if ((d && d.redefined() || d) === def) return;
}
node.object.walk(tw);

35
lib/scope.js
View File

@@ -190,7 +190,7 @@ AST_Toplevel.DEFMETHOD("figure_out_scope", function(options) {
function entangle(defun, scope) {
if (defun === scope) return;
node.mark_enclosed(options);
var def = scope.find_variable(node);
var def = scope.find_variable(node.name);
if (node.thedef === def) return;
node.thedef = def;
def.orig.push(node);
@@ -219,6 +219,21 @@ AST_Toplevel.DEFMETHOD("figure_out_scope", function(options) {
if (node.label) node.label.thedef.references.push(node);
return true;
}
// ensure mangling works if `catch` reuses a scope variable
if (node instanceof AST_SymbolCatch) {
var def = node.definition().redefined();
if (def) for (var s = node.scope; s; s = s.parent_scope) {
push_uniq(s.enclosed, def);
if (s === def.scope) break;
}
return true;
}
// ensure compression works if `const` reuses a scope variable
if (node instanceof AST_SymbolConst) {
var redef = node.definition().redefined();
if (redef) redef.const_redefs = true;
return true;
}
if (node instanceof AST_SymbolRef) {
var name = node.name;
var sym = node.scope.find_variable(name);
@@ -258,21 +273,6 @@ AST_Toplevel.DEFMETHOD("figure_out_scope", function(options) {
node.reference(options);
return true;
}
// ensure mangling works if `catch` reuses a scope variable
if (node instanceof AST_SymbolCatch) {
var def = node.definition().redefined();
if (def) for (var s = node.scope; s; s = s.parent_scope) {
push_uniq(s.enclosed, def);
if (s === def.scope) break;
}
return true;
}
// ensure compression works if `const` reuses a scope variable
if (node instanceof AST_SymbolConst) {
var redef = node.definition().redefined();
if (redef) redef.const_redefs = true;
return true;
}
});
self.walk(tw);
@@ -390,9 +390,8 @@ AST_Symbol.DEFMETHOD("reference", function(options) {
});
AST_BlockScope.DEFMETHOD("find_variable", function(name) {
if (name instanceof AST_Symbol) name = name.name;
return this.variables.get(name)
|| (this.parent_scope && this.parent_scope.find_variable(name));
|| this.parent_scope && this.parent_scope.find_variable(name);
});
AST_BlockScope.DEFMETHOD("def_function", function(symbol, init) {

29
test/compress/destructured.js
View File

@@ -1777,3 +1777,32 @@ issue_4323: {
expect_stdout: "function"
node_version: ">=6"
}
issue_4355: {
options = {
loops: true,
unused: true,
}
input: {
var a;
(function({
[function() {
for (a in "foo");
}()]: b,
}) {
var a;
})(0);
console.log(a);
}
expect: {
var a;
(function({
[function() {
for (a in "foo");
}()]: b,
}) {})(0);
console.log(a);
}
expect_stdout: "2"
node_version: ">=6"
}