[parser] Compute IsPrivateName from the underlying string on-the-fly

Change-Id: Ib9f51cab17a3ed9e8960857e77fc80a9a08df798
Reviewed-on: https://chromium-review.googlesource.com/c/1400841Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Toon Verwaest <verwaest@chromium.org>
Cr-Commit-Position: refs/heads/master@{#58660}

src/ast/ast.h

@@ -1628,9 +1628,8 @@ class VariableProxy final : public Expression {
         HoleCheckModeField::update(bit_field_, HoleCheckMode::kRequired);
   }
 
-  bool is_private_name() const { return IsPrivateName::decode(bit_field_); }
-  void set_is_private_name() {
-    bit_field_ = IsPrivateName::update(bit_field_, true);
+  bool IsPrivateName() const {
+    return raw_name()->length() > 0 && raw_name()->FirstCharacter() == '#';
   }
 
   // Bind this proxy to the variable var.
@@ -1687,8 +1686,7 @@ class VariableProxy final : public Expression {
                   IsAssignedField::encode(false) |
                   IsResolvedField::encode(false) |
                   IsRemovedFromUnresolvedField::encode(false) |
-                  HoleCheckModeField::encode(HoleCheckMode::kElided) |
-                  IsPrivateName::encode(false);
+                  HoleCheckModeField::encode(HoleCheckMode::kElided);
   }
 
   explicit VariableProxy(const VariableProxy* copy_from);
@@ -1703,7 +1701,6 @@ class VariableProxy final : public Expression {
       : public BitField<bool, IsRemovedFromUnresolvedField::kNext, 1> {};
   class HoleCheckModeField
       : public BitField<HoleCheckMode, IsNewTargetField::kNext, 1> {};
-  class IsPrivateName : public BitField<bool, HoleCheckModeField::kNext, 1> {};
 
   union {
     const AstRawString* raw_name_;  // if !is_resolved_

src/ast/scopes.cc

@@ -1421,7 +1421,7 @@ void Scope::AnalyzePartially(DeclarationScope* max_outer_scope,
       // reference to a private name or method. In that case keep it so we
       // can fail later.
       if (!max_outer_scope->outer_scope()->is_script_scope() ||
-          proxy->is_private_name()) {
+          proxy->IsPrivateName()) {
         VariableProxy* copy = ast_node_factory->CopyVariableProxy(proxy);
         new_unresolved_list->Add(copy);
       }
@@ -1845,7 +1845,7 @@ Variable* Scope::Lookup(VariableProxy* proxy, Scope* scope,
   if (mode == kParsedScope && !scope->is_script_scope()) {
     return nullptr;
   }
-  if (V8_UNLIKELY(proxy->is_private_name())) return nullptr;
+  if (V8_UNLIKELY(proxy->IsPrivateName())) return nullptr;
 
   // No binding has been found. Declare a variable on the global object.
   return scope->AsDeclarationScope()->DeclareDynamicGlobal(
@@ -1954,7 +1954,7 @@ bool Scope::ResolveVariable(ParseInfo* info, VariableProxy* proxy) {
   DCHECK(!proxy->is_resolved());
   Variable* var = Lookup<kParsedScope>(proxy, this, nullptr);
   if (var == nullptr) {
-    DCHECK(proxy->is_private_name());
+    DCHECK(proxy->IsPrivateName());
     info->pending_error_handler()->ReportMessageAt(
         proxy->position(), proxy->position() + 1,
         MessageTemplate::kInvalidPrivateFieldResolution, proxy->raw_name(),
@@ -2072,7 +2072,7 @@ bool Scope::ResolveVariablesRecursively(ParseInfo* info) {
             proxy->position(), proxy->position() + 1,
             MessageTemplate::kInvalidPrivateFieldResolution, proxy->raw_name(),
             kSyntaxError);
-        DCHECK(proxy->is_private_name());
+        DCHECK(proxy->IsPrivateName());
         return false;
       }
       if (!var->is_dynamic()) {

src/parsing/parser-base.h

@@ -1509,10 +1509,7 @@ ParserBase<Impl>::ParsePropertyOrPrivatePropertyName() {
     key = factory()->NewStringLiteral(name, pos);
   } else if (allow_harmony_private_fields() && next == Token::PRIVATE_NAME) {
     name = impl()->GetSymbol();
-    auto key_proxy =
-        impl()->ExpressionFromIdentifier(name, pos, InferName::kNo);
-    key_proxy->set_is_private_name();
-    key = key_proxy;
+    key = impl()->ExpressionFromIdentifier(name, pos, InferName::kNo);
   } else {
     ReportUnexpectedToken(next);
     return impl()->FailureExpression();

src/parsing/parser.cc

@@ -3158,7 +3158,7 @@ bool Parser::IsPropertyWithPrivateFieldKey(Expression* expression) {
   if (!property->key()->IsVariableProxy()) return false;
   VariableProxy* key = property->key()->AsVariableProxy();
 
-  return key->is_private_name();
+  return key->IsPrivateName();
 }
 
 void Parser::InsertShadowingVarBindingInitializers(Block* inner_block) {

src/parsing/preparser.h

@@ -325,15 +325,6 @@ class PreParserExpression {
   // and PreParser.
   PreParserExpression* operator->() { return this; }
 
-  void set_is_private_name() {
-    if (variables_ != nullptr) {
-      DCHECK(IsIdentifier());
-      DCHECK(AsIdentifier().IsPrivateName());
-      DCHECK_EQ(1, variables_->LengthForTest());
-      variables_->first()->set_is_private_name();
-    }
-  }
-
   // More dummy implementations of things PreParser doesn't need to track:
   void SetShouldEagerCompile() {}
   void mark_as_iife() {}