[parser] Simplify Scope::Declare

Change-Id: I3f2f6f82af84489f0563fa74c315e46b9c746325
Reviewed-on: https://chromium-review.googlesource.com/c/1322950
Commit-Queue: Toon Verwaest <verwaest@chromium.org>
Reviewed-by: Igor Sheludko <ishell@chromium.org>
Cr-Commit-Position: refs/heads/master@{#57318}

src/ast/scopes.cc

@@ -48,19 +48,20 @@ Variable* VariableMap::Declare(Zone* zone, Scope* scope,
                                VariableKind kind,
                                InitializationFlag initialization_flag,
                                MaybeAssignedFlag maybe_assigned_flag,
-                               bool* added) {
+                               base::ThreadedList<Variable>* variable_list) {
   // AstRawStrings are unambiguous, i.e., the same string is always represented
   // by the same AstRawString*.
   // FIXME(marja): fix the type of Lookup.
   Entry* p =
       ZoneHashMap::LookupOrInsert(const_cast<AstRawString*>(name), name->Hash(),
                                   ZoneAllocationPolicy(zone));
-  if (added) *added = p->value == nullptr;
   if (p->value == nullptr) {
     // The variable has not been declared yet -> insert it.
     DCHECK_EQ(name, p->key);
-    p->value = new (zone) Variable(scope, name, mode, kind, initialization_flag,
-                                   maybe_assigned_flag);
+    Variable* variable = new (zone) Variable(
+        scope, name, mode, kind, initialization_flag, maybe_assigned_flag);
+    if (variable_list) variable_list->Add(variable);
+    p->value = variable;
   }
   return reinterpret_cast<Variable*>(p->value);
 }
@@ -850,18 +851,6 @@ void DeclarationScope::AddLocal(Variable* var) {
   locals_.Add(var);
 }
 
-Variable* Scope::Declare(Zone* zone, const AstRawString* name,
-                         VariableMode mode, VariableKind kind,
-                         InitializationFlag initialization_flag,
-                         MaybeAssignedFlag maybe_assigned_flag) {
-  bool added;
-  Variable* var =
-      variables_.Declare(zone, this, name, mode, kind, initialization_flag,
-                         maybe_assigned_flag, &added);
-  if (added) locals_.Add(var);
-  return var;
-}
-
 void Scope::Snapshot::Reparent(DeclarationScope* new_parent) const {
   DCHECK_EQ(new_parent, outer_scope_and_calls_eval_.GetPointer()->inner_scope_);
   DCHECK_EQ(new_parent->outer_scope_, outer_scope_and_calls_eval_.GetPointer());

src/ast/scopes.h

@@ -37,7 +37,7 @@ class VariableMap: public ZoneHashMap {
       VariableKind kind = NORMAL_VARIABLE,
       InitializationFlag initialization_flag = kCreatedInitialized,
       MaybeAssignedFlag maybe_assigned_flag = kNotAssigned,
-      bool* added = nullptr);
+      base::ThreadedList<Variable>* variable_list = nullptr);
 
   // Records that "name" exists (if not recorded yet) but doesn't create a
   // Variable. Useful for preparsing.
@@ -497,7 +497,10 @@ class V8_EXPORT_PRIVATE Scope : public NON_EXPORTED_BASE(ZoneObject) {
       Zone* zone, const AstRawString* name, VariableMode mode,
       VariableKind kind = NORMAL_VARIABLE,
       InitializationFlag initialization_flag = kCreatedInitialized,
-      MaybeAssignedFlag maybe_assigned_flag = kNotAssigned);
+      MaybeAssignedFlag maybe_assigned_flag = kNotAssigned) {
+    return variables_.Declare(zone, this, name, mode, kind, initialization_flag,
+                              maybe_assigned_flag, &locals_);
+  }
 
   // This method should only be invoked on scopes created during parsing (i.e.,
   // not deserialized from a context). Also, since NeedsContext() is only