Refactor scope and function state tracking in (Pre)Parser.

src/parser.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 446 matching lines @@
   }
 
  private:
   Target** variable_;
   Target* previous_;
 };
 
 
 // ----------------------------------------------------------------------------
 // FunctionState and BlockState together implement the parser's scope stack.
-// The parser's current scope is in top_scope_.  The BlockState and
+// The parser's current scope is in scope_.  The BlockState and
 // FunctionState constructors push on the scope stack and the destructors
 // pop.  They are also used to hold the parser's per-function and per-block
 // state.
 
 class Parser::BlockState BASE_EMBEDDED {
  public:
-  BlockState(Parser* parser, Scope* scope)
-      : parser_(parser),
-        outer_scope_(parser->top_scope_) {
-    parser->top_scope_ = scope;
+  BlockState(Scope** scope_stack, Scope* scope)
+      : scope_stack_(scope_stack),
+        outer_scope_(*scope_stack) {
+    *scope_stack = scope;
   }
 
-  ~BlockState() { parser_->top_scope_ = outer_scope_; }
+  ~BlockState() { *scope_stack_ = outer_scope_; }
 
  private:
-  Parser* parser_;
+  Scope** scope_stack_;
   Scope* outer_scope_;
 };
 
 
-Parser::FunctionState::FunctionState(Parser* parser, Scope* scope)
+Parser::FunctionState::FunctionState(FunctionState** function_state_stack,
+                                     Scope** scope_stack, Scope* scope,
+                                     Zone* zone)
     : next_materialized_literal_index_(JSFunction::kLiteralsPrefixSize),
       next_handler_index_(0),
       expected_property_count_(0),
       generator_object_variable_(NULL),
-      parser_(parser),
-      outer_function_state_(parser->current_function_state_),
-      outer_scope_(parser->top_scope_),
-      saved_ast_node_id_(parser->zone()->isolate()->ast_node_id()),
-      factory_(parser->zone()) {
-  parser->top_scope_ = scope;
-  parser->current_function_state_ = this;
-  parser->zone()->isolate()->set_ast_node_id(BailoutId::FirstUsable().ToInt());
+      function_state_stack_(function_state_stack),
+      outer_function_state_(*function_state_stack),
+      scope_stack_(scope_stack),
+      outer_scope_(*scope_stack),

[ulan, 2014/02/12 10:16:51]

We have two many scope stacks =)
Does this precondition hold: *scope_stack == scope->outer_scope_?
If yes could you assert this or get rid of outer_scope_ here.

[marja, 2014/02/12 11:36:56]

It doesn't hold. In Parser::ParseLazy we seem to push a scope to the scope stack
which has outer_scope == NULL, even though there are some scopes in the stack
already. Scope::DeserializeScopeChain seems to complicate things.

-> outer_scope_ was here for a reason, leaving it like this.

+      isolate_(zone->isolate()),
+      saved_ast_node_id_(isolate_->ast_node_id()),
+      factory_(zone) {
+  *scope_stack_ = scope;
+  *function_state_stack = this;
+  isolate_->set_ast_node_id(BailoutId::FirstUsable().ToInt());
 }
 
 
 Parser::FunctionState::~FunctionState() {
-  parser_->top_scope_ = outer_scope_;
-  parser_->current_function_state_ = outer_function_state_;
+  *scope_stack_ = outer_scope_;
+  *function_state_stack_ = outer_function_state_;
   if (outer_function_state_ != NULL) {
-    parser_->isolate()->set_ast_node_id(saved_ast_node_id_);
+    isolate_->set_ast_node_id(saved_ast_node_id_);
   }
 }
 
 
 // ----------------------------------------------------------------------------
 // The CHECK_OK macro is a convenient macro to enforce error
 // handling for functions that may fail (by returning !*ok).
 //
 // CAUTION: This macro appends extra statements after a call,
 // thus it must never be used where only a single statement
 // is correct (e.g. an if statement branch w/o braces)!
 
 #define CHECK_OK  ok);   \
   if (!*ok) return NULL; \
   ((void)0
 #define DUMMY )  // to make indentation work
 #undef DUMMY
 
 #define CHECK_FAILED  /**/);   \
   if (failed_) return NULL; \
   ((void)0
 #define DUMMY )  // to make indentation work
 #undef DUMMY
 
 // ----------------------------------------------------------------------------
 // Implementation of Parser
 
 bool ParserTraits::is_classic_mode() const {
-  return parser_->top_scope_->is_classic_mode();
+  return parser_->scope_->is_classic_mode();
 }
 
 
 bool ParserTraits::is_generator() const {
-  return parser_->current_function_state_->is_generator();
+  return parser_->function_state_->is_generator();
 }
 
 
 bool ParserTraits::IsEvalOrArguments(Handle<String> identifier) const {
   return identifier.is_identical_to(
              parser_->isolate()->factory()->eval_string()) ||
          identifier.is_identical_to(
              parser_->isolate()->factory()->arguments_string());
 }
 
 
 int ParserTraits::NextMaterializedLiteralIndex() {
-  return parser_->current_function_state_->NextMaterializedLiteralIndex();
+  return parser_->function_state_->NextMaterializedLiteralIndex();
 }
 
 
 void ParserTraits::ReportMessageAt(Scanner::Location source_location,
                                    const char* message,
                                    Vector<const char*> args) {
   MessageLocation location(parser_->script_,
                            source_location.beg_pos,
                            source_location.end_pos);
   Factory* factory = parser_->isolate()->factory();
@@ skipping 63 matching lines @@
 
 Parser::Parser(CompilationInfo* info)
     : ParserBase<ParserTraits>(&scanner_,
                                info->isolate()->stack_guard()->real_climit(),
                                this),
       isolate_(info->isolate()),
       symbol_cache_(0, info->zone()),
       script_(info->script()),
       scanner_(isolate_->unicode_cache()),
       reusable_preparser_(NULL),
-      top_scope_(NULL),
+      scope_(NULL),
       original_scope_(NULL),
-      current_function_state_(NULL),
+      function_state_(NULL),
       target_stack_(NULL),
       extension_(info->extension()),
       pre_parse_data_(NULL),
       fni_(NULL),
       parenthesized_function_(false),
       zone_(info->zone()),
       info_(info) {
   ASSERT(!script_.is_null());
   isolate_->set_ast_node_id(0);
   set_allow_harmony_scoping(!info->is_native() && FLAG_harmony_scoping);
@@ skipping 47 matching lines @@
       PrintF("[parsing script");
     }
     PrintF(" - took %0.3f ms]\n", ms);
   }
   return result;
 }
 
 
 FunctionLiteral* Parser::DoParseProgram(CompilationInfo* info,
                                         Handle<String> source) {
-  ASSERT(top_scope_ == NULL);
+  ASSERT(scope_ == NULL);
   ASSERT(target_stack_ == NULL);
   if (pre_parse_data_ != NULL) pre_parse_data_->Initialize();
 
   Handle<String> no_name = isolate()->factory()->empty_string();
 
   FunctionLiteral* result = NULL;
-  { Scope* scope = NewScope(top_scope_, GLOBAL_SCOPE);
+  { Scope* scope = NewScope(scope_, GLOBAL_SCOPE);
     info->SetGlobalScope(scope);
     if (!info->context().is_null()) {
       scope = Scope::DeserializeScopeChain(*info->context(), scope, zone());
     }
     original_scope_ = scope;
     if (info->is_eval()) {
       if (!scope->is_global_scope() || info->language_mode() != CLASSIC_MODE) {
         scope = NewScope(scope, EVAL_SCOPE);
       }
     } else if (info->is_global()) {
       scope = NewScope(scope, GLOBAL_SCOPE);
     }
     scope->set_start_position(0);
     scope->set_end_position(source->length());
 
     // Compute the parsing mode.
     Mode mode = (FLAG_lazy && allow_lazy()) ? PARSE_LAZILY : PARSE_EAGERLY;
     if (allow_natives_syntax() ||
         extension_ != NULL ||
         scope->is_eval_scope()) {
       mode = PARSE_EAGERLY;
     }
     ParsingModeScope parsing_mode(this, mode);
 
     // Enters 'scope'.
-    FunctionState function_state(this, scope);
+    FunctionState function_state(&function_state_, &scope_, scope, zone());
 
-    top_scope_->SetLanguageMode(info->language_mode());
+    scope_->SetLanguageMode(info->language_mode());
     ZoneList<Statement*>* body = new(zone()) ZoneList<Statement*>(16, zone());
     bool ok = true;
     int beg_pos = scanner().location().beg_pos;
     ParseSourceElements(body, Token::EOS, info->is_eval(), true, &ok);
-    if (ok && !top_scope_->is_classic_mode()) {
+    if (ok && !scope_->is_classic_mode()) {
       CheckOctalLiteral(beg_pos, scanner().location().end_pos, &ok);
     }
 
     if (ok && is_extended_mode()) {
-      CheckConflictingVarDeclarations(top_scope_, &ok);
+      CheckConflictingVarDeclarations(scope_, &ok);
     }
 
     if (ok && info->parse_restriction() == ONLY_SINGLE_FUNCTION_LITERAL) {
       if (body->length() != 1 ||
           !body->at(0)->IsExpressionStatement() ||
           !body->at(0)->AsExpressionStatement()->
               expression()->IsFunctionLiteral()) {
         ReportMessage("single_function_literal", Vector<const char*>::empty());
         ok = false;
       }
     }
 
     if (ok) {
       result = factory()->NewFunctionLiteral(
           no_name,
-          top_scope_,
+          scope_,
           body,
           function_state.materialized_literal_count(),
           function_state.expected_property_count(),
           function_state.handler_count(),
           0,
           FunctionLiteral::kNoDuplicateParameters,
           FunctionLiteral::ANONYMOUS_EXPRESSION,
           FunctionLiteral::kGlobalOrEval,
           FunctionLiteral::kNotParenthesized,
           FunctionLiteral::kNotGenerator,
@@ skipping 45 matching lines @@
     SmartArrayPointer<char> name_chars = result->debug_name()->ToCString();
     PrintF("[parsing function: %s - took %0.3f ms]\n", name_chars.get(), ms);
   }
   return result;
 }
 
 
 FunctionLiteral* Parser::ParseLazy(Utf16CharacterStream* source) {
   Handle<SharedFunctionInfo> shared_info = info()->shared_info();
   scanner_.Initialize(source);
-  ASSERT(top_scope_ == NULL);
+  ASSERT(scope_ == NULL);
   ASSERT(target_stack_ == NULL);
 
   Handle<String> name(String::cast(shared_info->name()));
   fni_ = new(zone()) FuncNameInferrer(isolate(), zone());
   fni_->PushEnclosingName(name);
 
   ParsingModeScope parsing_mode(this, PARSE_EAGERLY);
 
   // Place holder for the result.
   FunctionLiteral* result = NULL;
 
   {
     // Parse the function literal.
-    Scope* scope = NewScope(top_scope_, GLOBAL_SCOPE);
+    Scope* scope = NewScope(scope_, GLOBAL_SCOPE);
     info()->SetGlobalScope(scope);
     if (!info()->closure().is_null()) {
       scope = Scope::DeserializeScopeChain(info()->closure()->context(), scope,
                                            zone());
     }
     original_scope_ = scope;
-    FunctionState function_state(this, scope);
+    FunctionState function_state(&function_state_, &scope_, scope, zone());
     ASSERT(scope->language_mode() != STRICT_MODE || !info()->is_classic_mode());
     ASSERT(scope->language_mode() != EXTENDED_MODE ||
            info()->is_extended_mode());
     ASSERT(info()->language_mode() == shared_info->language_mode());
     scope->SetLanguageMode(shared_info->language_mode());
     FunctionLiteral::FunctionType function_type = shared_info->is_expression()
         ? (shared_info->is_anonymous()
               ? FunctionLiteral::ANONYMOUS_EXPRESSION
               : FunctionLiteral::NAMED_EXPRESSION)
         : FunctionLiteral::DECLARATION;
@@ skipping 60 matching lines @@
       // A shot at a directive.
       ExpressionStatement* e_stat;
       Literal* literal;
       // Still processing directive prologue?
       if ((e_stat = stat->AsExpressionStatement()) != NULL &&
           (literal = e_stat->expression()->AsLiteral()) != NULL &&
           literal->value()->IsString()) {
         Handle<String> directive = Handle<String>::cast(literal->value());
 
         // Check "use strict" directive (ES5 14.1).
-        if (top_scope_->is_classic_mode() &&
+        if (scope_->is_classic_mode() &&
             directive->Equals(isolate()->heap()->use_strict_string()) &&
             token_loc.end_pos - token_loc.beg_pos ==
               isolate()->heap()->use_strict_string()->length() + 2) {
           // TODO(mstarzinger): Global strict eval calls, need their own scope
           // as specified in ES5 10.4.2(3). The correct fix would be to always
           // add this scope in DoParseProgram(), but that requires adaptations
           // all over the code base, so we go with a quick-fix for now.
           // In the same manner, we have to patch the parsing mode.
-          if (is_eval && !top_scope_->is_eval_scope()) {
-            ASSERT(top_scope_->is_global_scope());
-            Scope* scope = NewScope(top_scope_, EVAL_SCOPE);
-            scope->set_start_position(top_scope_->start_position());
-            scope->set_end_position(top_scope_->end_position());
-            top_scope_ = scope;
+          if (is_eval && !scope_->is_eval_scope()) {
+            ASSERT(scope_->is_global_scope());
+            Scope* scope = NewScope(scope_, EVAL_SCOPE);
+            scope->set_start_position(scope_->start_position());
+            scope->set_end_position(scope_->end_position());
+            scope_ = scope;
             mode_ = PARSE_EAGERLY;
           }
           // TODO(ES6): Fix entering extended mode, once it is specified.
-          top_scope_->SetLanguageMode(allow_harmony_scoping()
+          scope_->SetLanguageMode(allow_harmony_scoping()
                                       ? EXTENDED_MODE : STRICT_MODE);
           // "use strict" is the only directive for now.
           directive_prologue = false;
         }
       } else {
         // End of the directive prologue.
         directive_prologue = false;
       }
     }
 
@@ skipping 60 matching lines @@
   Handle<String> name = ParseIdentifier(kDontAllowEvalOrArguments, CHECK_OK);
 
 #ifdef DEBUG
   if (FLAG_print_interface_details)
     PrintF("# Module %s...\n", name->ToAsciiArray());
 #endif
 
   Module* module = ParseModule(CHECK_OK);
   VariableProxy* proxy = NewUnresolved(name, MODULE, module->interface());
   Declaration* declaration =
-      factory()->NewModuleDeclaration(proxy, module, top_scope_, pos);
+      factory()->NewModuleDeclaration(proxy, module, scope_, pos);
   Declare(declaration, true, CHECK_OK);
 
 #ifdef DEBUG
   if (FLAG_print_interface_details)
     PrintF("# Module %s.\n", name->ToAsciiArray());
 
   if (FLAG_print_interfaces) {
     PrintF("module %s : ", name->ToAsciiArray());
     module->interface()->Print();
   }
@@ skipping 37 matching lines @@
 Module* Parser::ParseModuleLiteral(bool* ok) {
   // Module:
   //    '{' ModuleElement '}'
 
   int pos = peek_position();
   // Construct block expecting 16 statements.
   Block* body = factory()->NewBlock(NULL, 16, false, RelocInfo::kNoPosition);
 #ifdef DEBUG
   if (FLAG_print_interface_details) PrintF("# Literal ");
 #endif
-  Scope* scope = NewScope(top_scope_, MODULE_SCOPE);
+  Scope* scope = NewScope(scope_, MODULE_SCOPE);
 
   Expect(Token::LBRACE, CHECK_OK);
   scope->set_start_position(scanner().location().beg_pos);
   scope->SetLanguageMode(EXTENDED_MODE);
 
   {
-    BlockState block_state(this, scope);
+    BlockState block_state(&scope_, scope);
     TargetCollector collector(zone());
     Target target(&this->target_stack_, &collector);
     Target target_body(&this->target_stack_, body);
 
     while (peek() != Token::RBRACE) {
       Statement* stat = ParseModuleElement(NULL, CHECK_OK);
       if (stat && !stat->IsEmpty()) {
         body->AddStatement(stat, zone());
       }
     }
@@ skipping 63 matching lines @@
 Module* Parser::ParseModuleVariable(bool* ok) {
   // ModulePath:
   //    Identifier
 
   int pos = peek_position();
   Handle<String> name = ParseIdentifier(kDontAllowEvalOrArguments, CHECK_OK);
 #ifdef DEBUG
   if (FLAG_print_interface_details)
     PrintF("# Module variable %s ", name->ToAsciiArray());
 #endif
-  VariableProxy* proxy = top_scope_->NewUnresolved(
+  VariableProxy* proxy = scope_->NewUnresolved(
       factory(), name, Interface::NewModule(zone()),
       scanner().location().beg_pos);
 
   return factory()->NewModuleVariable(proxy, pos);
 }
 
 
 Module* Parser::ParseModuleUrl(bool* ok) {
   // Module:
   //    String
 
   int pos = peek_position();
   Expect(Token::STRING, CHECK_OK);
   Handle<String> symbol = GetSymbol();
 
   // TODO(ES6): Request JS resource from environment...
 
 #ifdef DEBUG
   if (FLAG_print_interface_details) PrintF("# Url ");
 #endif
 
   // Create an empty literal as long as the feature isn't finished.
   USE(symbol);
-  Scope* scope = NewScope(top_scope_, MODULE_SCOPE);
+  Scope* scope = NewScope(scope_, MODULE_SCOPE);
   Block* body = factory()->NewBlock(NULL, 1, false, RelocInfo::kNoPosition);
   body->set_scope(scope);
   Interface* interface = scope->interface();
   Module* result = factory()->NewModuleLiteral(body, interface, pos);
   interface->Freeze(ok);
   ASSERT(*ok);
   interface->Unify(scope->interface(), zone(), ok);
   ASSERT(*ok);
   return result;
 }
@@ skipping 51 matching lines @@
         PrintF("module: ");
         module->interface()->Print();
       }
 #endif
       ParserTraits::ReportMessage("invalid_module_path",
                                   Vector<Handle<String> >(&name, 1));
       return NULL;
     }
     VariableProxy* proxy = NewUnresolved(names[i], LET, interface);
     Declaration* declaration =
-        factory()->NewImportDeclaration(proxy, module, top_scope_, pos);
+        factory()->NewImportDeclaration(proxy, module, scope_, pos);
     Declare(declaration, true, CHECK_OK);
   }
 
   return block;
 }
 
 
 Statement* Parser::ParseExportDeclaration(bool* ok) {
   // ExportDeclaration:
   //    'export' Identifier (',' Identifier)* ';'
@@ skipping 39 matching lines @@
       result = ParseVariableStatement(kModuleElement, &names, CHECK_OK);
       break;
 
     default:
       *ok = false;
       ReportUnexpectedToken(scanner().current_token());
       return NULL;
   }
 
   // Extract declared names into export declarations and interface.
-  Interface* interface = top_scope_->interface();
+  Interface* interface = scope_->interface();
   for (int i = 0; i < names.length(); ++i) {
 #ifdef DEBUG
     if (FLAG_print_interface_details)
       PrintF("# Export %s ", names[i]->ToAsciiArray());
 #endif
     Interface* inner = Interface::NewUnknown(zone());
     interface->Add(names[i], inner, zone(), CHECK_OK);
     if (!*ok)
       return NULL;
     VariableProxy* proxy = NewUnresolved(names[i], LET, inner);
     USE(proxy);
     // TODO(rossberg): Rethink whether we actually need to store export
     // declarations (for compilation?).
     // ExportDeclaration* declaration =
-    //     factory()->NewExportDeclaration(proxy, top_scope_, position);
-    // top_scope_->AddDeclaration(declaration);
+    //     factory()->NewExportDeclaration(proxy, scope_, position);
+    // scope_->AddDeclaration(declaration);
   }
 
   ASSERT(result != NULL);
   return result;
 }
 
 
 Statement* Parser::ParseBlockElement(ZoneStringList* labels,
                                      bool* ok) {
   // (Ecma 262 5th Edition, clause 14):
@@ skipping 105 matching lines @@
       // (Ecma 262 5th Edition, clause 14):
       // SourceElement:
       //    Statement
       //    FunctionDeclaration
       // Common language extension is to allow function declaration in place
       // of any statement. This language extension is disabled in strict mode.
       //
       // In Harmony mode, this case also handles the extension:
       // Statement:
       //    GeneratorDeclaration
-      if (!top_scope_->is_classic_mode()) {
+      if (!scope_->is_classic_mode()) {
         ReportMessageAt(scanner().peek_location(), "strict_function");
         *ok = false;
         return NULL;
       }
       return ParseFunctionDeclaration(NULL, ok);
     }
 
     case Token::DEBUGGER:
       return ParseDebuggerStatement(ok);
 
@@ skipping 199 matching lines @@
   // isn't lazily compiled. The extension structures are only
   // accessible while parsing the first time not when reparsing
   // because of lazy compilation.
   DeclarationScope(VAR)->ForceEagerCompilation();
 
   // TODO(1240846): It's weird that native function declarations are
   // introduced dynamically when we meet their declarations, whereas
   // other functions are set up when entering the surrounding scope.
   VariableProxy* proxy = NewUnresolved(name, VAR, Interface::NewValue());
   Declaration* declaration =
-      factory()->NewVariableDeclaration(proxy, VAR, top_scope_, pos);
+      factory()->NewVariableDeclaration(proxy, VAR, scope_, pos);
   Declare(declaration, true, CHECK_OK);
   NativeFunctionLiteral* lit = factory()->NewNativeFunctionLiteral(
       name, extension_, RelocInfo::kNoPosition);
   return factory()->NewExpressionStatement(
       factory()->NewAssignment(
           Token::INIT_VAR, proxy, lit, RelocInfo::kNoPosition),
       pos);
 }
 
 
@@ skipping 15 matching lines @@
                                               is_generator,
                                               pos,
                                               FunctionLiteral::DECLARATION,
                                               CHECK_OK);
   // Even if we're not at the top-level of the global or a function
   // scope, we treat it as such and introduce the function with its
   // initial value upon entering the corresponding scope.
   // In extended mode, a function behaves as a lexical binding, except in the
   // global scope.
   VariableMode mode =
-      is_extended_mode() && !top_scope_->is_global_scope() ? LET : VAR;
+      is_extended_mode() && !scope_->is_global_scope() ? LET : VAR;
   VariableProxy* proxy = NewUnresolved(name, mode, Interface::NewValue());
   Declaration* declaration =
-      factory()->NewFunctionDeclaration(proxy, mode, fun, top_scope_, pos);
+      factory()->NewFunctionDeclaration(proxy, mode, fun, scope_, pos);
   Declare(declaration, true, CHECK_OK);
   if (names) names->Add(name, zone());
   return factory()->NewEmptyStatement(RelocInfo::kNoPosition);
 }
 
 
 Block* Parser::ParseBlock(ZoneStringList* labels, bool* ok) {
-  if (top_scope_->is_extended_mode()) return ParseScopedBlock(labels, ok);
+  if (scope_->is_extended_mode()) return ParseScopedBlock(labels, ok);
 
   // Block ::
   //   '{' Statement* '}'
 
   // Note that a Block does not introduce a new execution scope!
   // (ECMA-262, 3rd, 12.2)
   //
   // Construct block expecting 16 statements.
   Block* result =
       factory()->NewBlock(labels, 16, false, RelocInfo::kNoPosition);
@@ skipping 12 matching lines @@
 
 Block* Parser::ParseScopedBlock(ZoneStringList* labels, bool* ok) {
   // The harmony mode uses block elements instead of statements.
   //
   // Block ::
   //   '{' BlockElement* '}'
 
   // Construct block expecting 16 statements.
   Block* body =
       factory()->NewBlock(labels, 16, false, RelocInfo::kNoPosition);
-  Scope* block_scope = NewScope(top_scope_, BLOCK_SCOPE);
+  Scope* block_scope = NewScope(scope_, BLOCK_SCOPE);
 
   // Parse the statements and collect escaping labels.
   Expect(Token::LBRACE, CHECK_OK);
   block_scope->set_start_position(scanner().location().beg_pos);
-  { BlockState block_state(this, block_scope);
+  { BlockState block_state(&scope_, block_scope);
     TargetCollector collector(zone());
     Target target(&this->target_stack_, &collector);
     Target target_body(&this->target_stack_, body);
 
     while (peek() != Token::RBRACE) {
       Statement* stat = ParseBlockElement(NULL, CHECK_OK);
       if (stat && !stat->IsEmpty()) {
         body->AddStatement(stat, zone());
       }
     }
@@ skipping 61 matching lines @@
     //
     // ConstDeclaration : const ConstBinding (',' ConstBinding)* ';'
     //
     // * It is a Syntax Error if the code that matches this production is not
     //   contained in extended code.
     //
     // However disallowing const in classic mode will break compatibility with
     // existing pages. Therefore we keep allowing const with the old
     // non-harmony semantics in classic mode.
     Consume(Token::CONST);
-    switch (top_scope_->language_mode()) {
+    switch (scope_->language_mode()) {
       case CLASSIC_MODE:
         mode = CONST;
         init_op = Token::INIT_CONST;
         break;
       case STRICT_MODE:
         ReportMessage("strict_const", Vector<const char*>::empty());
         *ok = false;
         return NULL;
       case EXTENDED_MODE:
         if (var_context == kStatement) {
@@ skipping 72 matching lines @@
     // If we have a const declaration, in an inner scope, the proxy is always
     // bound to the declared variable (independent of possibly surrounding with
     // statements).
     // For let/const declarations in harmony mode, we can also immediately
     // pre-resolve the proxy because it resides in the same scope as the
     // declaration.
     Interface* interface =
         is_const ? Interface::NewConst() : Interface::NewValue();
     VariableProxy* proxy = NewUnresolved(name, mode, interface);
     Declaration* declaration =
-        factory()->NewVariableDeclaration(proxy, mode, top_scope_, pos);
+        factory()->NewVariableDeclaration(proxy, mode, scope_, pos);
     Declare(declaration, mode != VAR, CHECK_OK);
     nvars++;
     if (declaration_scope->num_var_or_const() > kMaxNumFunctionLocals) {
       ReportMessageAt(scanner().location(), "too_many_variables");
       *ok = false;
       return NULL;
     }
     if (names) names->Add(name, zone());
 
     // Parse initialization expression if present and/or needed. A
     // declaration of the form:
     //
     //    var v = x;
     //
     // is syntactic sugar for:
     //
     //    var v; v = x;
     //
-    // In particular, we need to re-lookup 'v' (in top_scope_, not
+    // In particular, we need to re-lookup 'v' (in scope_, not
     // declaration_scope) as it may be a different 'v' than the 'v' in the
     // declaration (e.g., if we are inside a 'with' statement or 'catch'
     // block).
     //
     // However, note that const declarations are different! A const
     // declaration of the form:
     //
     //   const c = x;
     //
     // is *not* syntactic sugar for:
     //
     //   const c; c = x;
     //
     // The "variable" c initialized to x is the same as the declared
     // one - there is no re-lookup (see the last parameter of the
     // Declare() call above).
 
-    Scope* initialization_scope = is_const ? declaration_scope : top_scope_;
+    Scope* initialization_scope = is_const ? declaration_scope : scope_;
     Expression* value = NULL;
     int pos = -1;
     // Harmony consts have non-optional initializers.
     if (peek() == Token::ASSIGN || mode == CONST_HARMONY) {
       Expect(Token::ASSIGN, CHECK_OK);
       pos = position();
       value = ParseAssignmentExpression(var_context != kForStatement, CHECK_OK);
       // Don't infer if it is "a = function(){...}();"-like expression.
       if (fni_ != NULL &&
           value->AsCall() == NULL &&
@@ skipping 170 matching lines @@
       *ok = false;
       return NULL;
     }
     if (labels == NULL) {
       labels = new(zone()) ZoneStringList(4, zone());
     }
     labels->Add(label, zone());
     // Remove the "ghost" variable that turned out to be a label
     // from the top scope. This way, we don't try to resolve it
     // during the scope processing.
-    top_scope_->RemoveUnresolved(var);
+    scope_->RemoveUnresolved(var);
     Expect(Token::COLON, CHECK_OK);
     return ParseStatement(labels, ok);
   }
 
   // If we have an extension, we allow a native function declaration.
   // A native function declaration starts with "native function" with
   // no line-terminator between the two words.
   if (extension_ != NULL &&
       peek() == Token::FUNCTION &&
       !scanner().HasAnyLineTerminatorBeforeNext() &&
@@ skipping 129 matching lines @@
       tok == Token::SEMICOLON ||
       tok == Token::RBRACE ||
       tok == Token::EOS) {
     return_value = GetLiteralUndefined(position());
   } else {
     return_value = ParseExpression(true, CHECK_OK);
   }
   ExpectSemicolon(CHECK_OK);
   if (is_generator()) {
     Expression* generator = factory()->NewVariableProxy(
-        current_function_state_->generator_object_variable());
+        function_state_->generator_object_variable());
     Expression* yield = factory()->NewYield(
         generator, return_value, Yield::FINAL, pos);
     result = factory()->NewExpressionStatement(yield, pos);
   } else {
     result = factory()->NewReturnStatement(return_value, pos);
   }
 
   // An ECMAScript program is considered syntactically incorrect if it
   // contains a return statement that is not within the body of a
   // function. See ECMA-262, section 12.9, page 67.
   //
   // To be consistent with KJS we report the syntax error at runtime.
-  Scope* declaration_scope = top_scope_->DeclarationScope();
+  Scope* declaration_scope = scope_->DeclarationScope();
   if (declaration_scope->is_global_scope() ||
       declaration_scope->is_eval_scope()) {
     Handle<String> message = isolate()->factory()->illegal_return_string();
     Expression* throw_error =
         NewThrowSyntaxError(message, Handle<Object>::null());
     return factory()->NewExpressionStatement(throw_error, pos);
   }
   return result;
 }
 
 
 Statement* Parser::ParseWithStatement(ZoneStringList* labels, bool* ok) {
   // WithStatement ::
   //   'with' '(' Expression ')' Statement
 
   Expect(Token::WITH, CHECK_OK);
   int pos = position();
 
-  if (!top_scope_->is_classic_mode()) {
+  if (!scope_->is_classic_mode()) {
     ReportMessage("strict_mode_with", Vector<const char*>::empty());
     *ok = false;
     return NULL;
   }
 
   Expect(Token::LPAREN, CHECK_OK);
   Expression* expr = ParseExpression(true, CHECK_OK);
   Expect(Token::RPAREN, CHECK_OK);
 
-  top_scope_->DeclarationScope()->RecordWithStatement();
-  Scope* with_scope = NewScope(top_scope_, WITH_SCOPE);
+  scope_->DeclarationScope()->RecordWithStatement();
+  Scope* with_scope = NewScope(scope_, WITH_SCOPE);
   Statement* stmt;
-  { BlockState block_state(this, with_scope);
+  { BlockState block_state(&scope_, with_scope);
     with_scope->set_start_position(scanner().peek_location().beg_pos);
     stmt = ParseStatement(labels, CHECK_OK);
     with_scope->set_end_position(scanner().location().end_pos);
   }
   return factory()->NewWithStatement(with_scope, expr, stmt, pos);
 }
 
 
 CaseClause* Parser::ParseCaseClause(bool* default_seen_ptr, bool* ok) {
   // CaseClause ::
@@ skipping 111 matching lines @@
   // always collect the targets.
   TargetCollector catch_collector(zone());
   Scope* catch_scope = NULL;
   Variable* catch_variable = NULL;
   Block* catch_block = NULL;
   Handle<String> name;
   if (tok == Token::CATCH) {
     Consume(Token::CATCH);
 
     Expect(Token::LPAREN, CHECK_OK);
-    catch_scope = NewScope(top_scope_, CATCH_SCOPE);
+    catch_scope = NewScope(scope_, CATCH_SCOPE);
     catch_scope->set_start_position(scanner().location().beg_pos);
     name = ParseIdentifier(kDontAllowEvalOrArguments, CHECK_OK);
 
     Expect(Token::RPAREN, CHECK_OK);
 
     Target target(&this->target_stack_, &catch_collector);
     VariableMode mode = is_extended_mode() ? LET : VAR;
     catch_variable =
         catch_scope->DeclareLocal(name, mode, kCreatedInitialized);
 
-    BlockState block_state(this, catch_scope);
+    BlockState block_state(&scope_, catch_scope);
     catch_block = ParseBlock(NULL, CHECK_OK);
 
     catch_scope->set_end_position(scanner().location().end_pos);
     tok = peek();
   }
 
   Block* finally_block = NULL;
   ASSERT(tok == Token::FINALLY || catch_block != NULL);
   if (tok == Token::FINALLY) {
     Consume(Token::FINALLY);
     finally_block = ParseBlock(NULL, CHECK_OK);
   }
 
   // Simplify the AST nodes by converting:
   //   'try B0 catch B1 finally B2'
   // to:
   //   'try { try B0 catch B1 } finally B2'
 
   if (catch_block != NULL && finally_block != NULL) {
     // If we have both, create an inner try/catch.
     ASSERT(catch_scope != NULL && catch_variable != NULL);
-    int index = current_function_state_->NextHandlerIndex();
+    int index = function_state_->NextHandlerIndex();
     TryCatchStatement* statement = factory()->NewTryCatchStatement(
         index, try_block, catch_scope, catch_variable, catch_block,
         RelocInfo::kNoPosition);
     statement->set_escaping_targets(try_collector.targets());
     try_block = factory()->NewBlock(NULL, 1, false, RelocInfo::kNoPosition);
     try_block->AddStatement(statement, zone());
     catch_block = NULL;  // Clear to indicate it's been handled.
   }
 
   TryStatement* result = NULL;
   if (catch_block != NULL) {
     ASSERT(finally_block == NULL);
     ASSERT(catch_scope != NULL && catch_variable != NULL);
-    int index = current_function_state_->NextHandlerIndex();
+    int index = function_state_->NextHandlerIndex();
     result = factory()->NewTryCatchStatement(
         index, try_block, catch_scope, catch_variable, catch_block, pos);
   } else {
     ASSERT(finally_block != NULL);
-    int index = current_function_state_->NextHandlerIndex();
+    int index = function_state_->NextHandlerIndex();
     result = factory()->NewTryFinallyStatement(
         index, try_block, finally_block, pos);
     // Combine the jump targets of the try block and the possible catch block.
     try_collector.targets()->AddAll(*catch_collector.targets(), zone());
   }
 
   result->set_escaping_targets(try_collector.targets());
   return result;
 }
 
@@ skipping 59 matching lines @@
 
 
 void Parser::InitializeForEachStatement(ForEachStatement* stmt,
                                         Expression* each,
                                         Expression* subject,
                                         Statement* body) {
   ForOfStatement* for_of = stmt->AsForOfStatement();
 
   if (for_of != NULL) {
     Factory* heap_factory = isolate()->factory();
-    Variable* iterator = top_scope_->DeclarationScope()->NewTemporary(
+    Variable* iterator = scope_->DeclarationScope()->NewTemporary(
         heap_factory->dot_iterator_string());
-    Variable* result = top_scope_->DeclarationScope()->NewTemporary(
+    Variable* result = scope_->DeclarationScope()->NewTemporary(
         heap_factory->dot_result_string());
 
     Expression* assign_iterator;
     Expression* next_result;
     Expression* result_done;
     Expression* assign_each;
 
     // var iterator = iterable;
     {
       Expression* iterator_proxy = factory()->NewVariableProxy(iterator);
@@ skipping 46 matching lines @@
 
 
 Statement* Parser::ParseForStatement(ZoneStringList* labels, bool* ok) {
   // ForStatement ::
   //   'for' '(' Expression? ';' Expression? ';' Expression? ')' Statement
 
   int pos = peek_position();
   Statement* init = NULL;
 
   // Create an in-between scope for let-bound iteration variables.
-  Scope* saved_scope = top_scope_;
-  Scope* for_scope = NewScope(top_scope_, BLOCK_SCOPE);
-  top_scope_ = for_scope;
+  Scope* saved_scope = scope_;
+  Scope* for_scope = NewScope(scope_, BLOCK_SCOPE);
+  scope_ = for_scope;
 
   Expect(Token::FOR, CHECK_OK);
   Expect(Token::LPAREN, CHECK_OK);
   for_scope->set_start_position(scanner().location().beg_pos);
   if (peek() != Token::SEMICOLON) {
     if (peek() == Token::VAR || peek() == Token::CONST) {
       bool is_const = peek() == Token::CONST;
       Handle<String> name;
       VariableDeclarationProperties decl_props = kHasNoInitializers;
       Block* variable_statement =
           ParseVariableDeclarations(kForStatement, &decl_props, NULL, &name,
                                     CHECK_OK);
       bool accept_OF = decl_props == kHasNoInitializers;
       ForEachStatement::VisitMode mode;
 
       if (!name.is_null() && CheckInOrOf(accept_OF, &mode)) {
         Interface* interface =
             is_const ? Interface::NewConst() : Interface::NewValue();
         ForEachStatement* loop =
             factory()->NewForEachStatement(mode, labels, pos);
         Target target(&this->target_stack_, loop);
 
         Expression* enumerable = ParseExpression(true, CHECK_OK);
         Expect(Token::RPAREN, CHECK_OK);
 
         VariableProxy* each =
-            top_scope_->NewUnresolved(factory(), name, interface);
+            scope_->NewUnresolved(factory(), name, interface);
         Statement* body = ParseStatement(NULL, CHECK_OK);
         InitializeForEachStatement(loop, each, enumerable, body);
         Block* result =
             factory()->NewBlock(NULL, 2, false, RelocInfo::kNoPosition);
         result->AddStatement(variable_statement, zone());
         result->AddStatement(loop, zone());
-        top_scope_ = saved_scope;
+        scope_ = saved_scope;
         for_scope->set_end_position(scanner().location().end_pos);
         for_scope = for_scope->FinalizeBlockScope();
         ASSERT(for_scope == NULL);
         // Parsed for-in loop w/ variable/const declaration.
         return result;
       } else {
         init = variable_statement;
       }
     } else if (peek() == Token::LET) {
       Handle<String> name;
@@ skipping 18 matching lines @@
         //     x = x';
         //     b;
         //   }
 
         // TODO(keuchel): Move the temporary variable to the block scope, after
         // implementing stack allocated block scoped variables.
         Factory* heap_factory = isolate()->factory();
         Handle<String> tempstr =
             heap_factory->NewConsString(heap_factory->dot_for_string(), name);
         Handle<String> tempname = heap_factory->InternalizeString(tempstr);
-        Variable* temp = top_scope_->DeclarationScope()->NewTemporary(tempname);
+        Variable* temp = scope_->DeclarationScope()->NewTemporary(tempname);
         VariableProxy* temp_proxy = factory()->NewVariableProxy(temp);
         ForEachStatement* loop =
             factory()->NewForEachStatement(mode, labels, pos);
         Target target(&this->target_stack_, loop);
 
         // The expression does not see the loop variable.
-        top_scope_ = saved_scope;
+        scope_ = saved_scope;
         Expression* enumerable = ParseExpression(true, CHECK_OK);
-        top_scope_ = for_scope;
+        scope_ = for_scope;
         Expect(Token::RPAREN, CHECK_OK);
 
         VariableProxy* each =
-            top_scope_->NewUnresolved(factory(), name, Interface::NewValue());
+            scope_->NewUnresolved(factory(), name, Interface::NewValue());
         Statement* body = ParseStatement(NULL, CHECK_OK);
         Block* body_block =
             factory()->NewBlock(NULL, 3, false, RelocInfo::kNoPosition);
         Assignment* assignment = factory()->NewAssignment(
             Token::ASSIGN, each, temp_proxy, RelocInfo::kNoPosition);
         Statement* assignment_statement = factory()->NewExpressionStatement(
             assignment, RelocInfo::kNoPosition);
         body_block->AddStatement(variable_statement, zone());
         body_block->AddStatement(assignment_statement, zone());
         body_block->AddStatement(body, zone());
         InitializeForEachStatement(loop, temp_proxy, enumerable, body_block);
-        top_scope_ = saved_scope;
+        scope_ = saved_scope;
         for_scope->set_end_position(scanner().location().end_pos);
         for_scope = for_scope->FinalizeBlockScope();
         body_block->set_scope(for_scope);
         // Parsed for-in loop w/ let declaration.
         return loop;
 
       } else {
         init = variable_statement;
       }
     } else {
@@ skipping 13 matching lines @@
         }
         ForEachStatement* loop =
             factory()->NewForEachStatement(mode, labels, pos);
         Target target(&this->target_stack_, loop);
 
         Expression* enumerable = ParseExpression(true, CHECK_OK);
         Expect(Token::RPAREN, CHECK_OK);
 
         Statement* body = ParseStatement(NULL, CHECK_OK);
         InitializeForEachStatement(loop, expression, enumerable, body);
-        top_scope_ = saved_scope;
+        scope_ = saved_scope;
         for_scope->set_end_position(scanner().location().end_pos);
         for_scope = for_scope->FinalizeBlockScope();
         ASSERT(for_scope == NULL);
         // Parsed for-in loop.
         return loop;
 
       } else {
         init = factory()->NewExpressionStatement(
             expression, RelocInfo::kNoPosition);
       }
@@ skipping 14 matching lines @@
   Expect(Token::SEMICOLON, CHECK_OK);
 
   Statement* next = NULL;
   if (peek() != Token::RPAREN) {
     Expression* exp = ParseExpression(true, CHECK_OK);
     next = factory()->NewExpressionStatement(exp, RelocInfo::kNoPosition);
   }
   Expect(Token::RPAREN, CHECK_OK);
 
   Statement* body = ParseStatement(NULL, CHECK_OK);
-  top_scope_ = saved_scope;
+  scope_ = saved_scope;
   for_scope->set_end_position(scanner().location().end_pos);
   for_scope = for_scope->FinalizeBlockScope();
   if (for_scope != NULL) {
     // Rewrite a for statement of the form
     //
     //   for (let x = i; c; n) b
     //
     // into
     //
     //   {
@@ skipping 55 matching lines @@
   // side expression.  We could report this as a syntax error here but
   // for compatibility with JSC we choose to report the error at
   // runtime.
   // TODO(ES5): Should change parsing for spec conformance.
   if (expression == NULL || !expression->IsValidLeftHandSide()) {
     Handle<String> message =
         isolate()->factory()->invalid_lhs_in_assignment_string();
     expression = NewThrowReferenceError(message);
   }
 
-  if (!top_scope_->is_classic_mode()) {
+  if (!scope_->is_classic_mode()) {
     // Assignment to eval or arguments is disallowed in strict mode.
     CheckStrictModeLValue(expression, CHECK_OK);
   }
   MarkAsLValue(expression);
 
   Token::Value op = Next();  // Get assignment operator.
   int pos = position();
   Expression* right = ParseAssignmentExpression(accept_IN, CHECK_OK);
 
   // TODO(1231235): We try to estimate the set of properties set by
   // constructors. We define a new property whenever there is an
   // assignment to a property of 'this'. We should probably only add
   // properties if we haven't seen them before. Otherwise we'll
   // probably overestimate the number of properties.
   Property* property = expression ? expression->AsProperty() : NULL;
   if (op == Token::ASSIGN &&
       property != NULL &&
       property->obj()->AsVariableProxy() != NULL &&
       property->obj()->AsVariableProxy()->is_this()) {
-    current_function_state_->AddProperty();
+    function_state_->AddProperty();
   }
 
   // If we assign a function literal to a property we pretenure the
   // literal so it can be added as a constant function property.
   if (property != NULL && right->AsFunctionLiteral() != NULL) {
     right->AsFunctionLiteral()->set_pretenure();
   }
 
   if (fni_ != NULL) {
     // Check if the right hand side is a call to avoid inferring a
@@ skipping 15 matching lines @@
 
 
 Expression* Parser::ParseYieldExpression(bool* ok) {
   // YieldExpression ::
   //   'yield' '*'? AssignmentExpression
   int pos = peek_position();
   Expect(Token::YIELD, CHECK_OK);
   Yield::Kind kind =
       Check(Token::MUL) ? Yield::DELEGATING : Yield::SUSPEND;
   Expression* generator_object = factory()->NewVariableProxy(
-      current_function_state_->generator_object_variable());
+      function_state_->generator_object_variable());
   Expression* expression = ParseAssignmentExpression(false, CHECK_OK);
   Yield* yield = factory()->NewYield(generator_object, expression, kind, pos);
   if (kind == Yield::DELEGATING) {
-    yield->set_index(current_function_state_->NextHandlerIndex());
+    yield->set_index(function_state_->NextHandlerIndex());
   }
   return yield;
 }
 
 
 // Precedence = 3
 Expression* Parser::ParseConditionalExpression(bool accept_IN, bool* ok) {
   // ConditionalExpression ::
   //   LogicalOrExpression
   //   LogicalOrExpression '?' AssignmentExpression ':' AssignmentExpression
@@ skipping 143 matching lines @@
             return factory()->NewNumberLiteral(-value, pos);
           case Token::BIT_NOT:
             return factory()->NewNumberLiteral(~DoubleToInt32(value), pos);
           default:
             break;
         }
       }
     }
 
     // "delete identifier" is a syntax error in strict mode.
-    if (op == Token::DELETE && !top_scope_->is_classic_mode()) {
+    if (op == Token::DELETE && !scope_->is_classic_mode()) {
       VariableProxy* operand = expression->AsVariableProxy();
       if (operand != NULL && !operand->is_this()) {
         ReportMessage("strict_delete", Vector<const char*>::empty());
         *ok = false;
         return NULL;
       }
     }
 
     // Desugar '+foo' into 'foo*1', this enables the collection of type feedback
     // without any special stub and the multiplication is removed later in
@@ skipping 27 matching lines @@
     // Signal a reference error if the expression is an invalid
     // left-hand side expression.  We could report this as a syntax
     // error here but for compatibility with JSC we choose to report the
     // error at runtime.
     if (expression == NULL || !expression->IsValidLeftHandSide()) {
       Handle<String> message =
           isolate()->factory()->invalid_lhs_in_prefix_op_string();
       expression = NewThrowReferenceError(message);
     }
 
-    if (!top_scope_->is_classic_mode()) {
+    if (!scope_->is_classic_mode()) {
       // Prefix expression operand in strict mode may not be eval or arguments.
       CheckStrictModeLValue(expression, CHECK_OK);
     }
     MarkAsLValue(expression);
 
     return factory()->NewCountOperation(op,
                                         true /* prefix */,
                                         expression,
                                         position());
 
@@ skipping 13 matching lines @@
     // Signal a reference error if the expression is an invalid
     // left-hand side expression.  We could report this as a syntax
     // error here but for compatibility with JSC we choose to report the
     // error at runtime.
     if (expression == NULL || !expression->IsValidLeftHandSide()) {
       Handle<String> message =
           isolate()->factory()->invalid_lhs_in_postfix_op_string();
       expression = NewThrowReferenceError(message);
     }
 
-    if (!top_scope_->is_classic_mode()) {
+    if (!scope_->is_classic_mode()) {
       // Postfix expression operand in strict mode may not be eval or arguments.
       CheckStrictModeLValue(expression, CHECK_OK);
     }
     MarkAsLValue(expression);
 
     Token::Value next = Next();
     expression =
         factory()->NewCountOperation(next,
                                      false /* postfix */,
                                      expression,
@@ skipping 50 matching lines @@
         // Keep track of eval() calls since they disable all local variable
         // optimizations.
         // The calls that need special treatment are the
         // direct eval calls. These calls are all of the form eval(...), with
         // no explicit receiver.
         // These calls are marked as potentially direct eval calls. Whether
         // they are actually direct calls to eval is determined at run time.
         VariableProxy* callee = result->AsVariableProxy();
         if (callee != NULL &&
             callee->IsVariable(isolate()->factory()->eval_string())) {
-          top_scope_->DeclarationScope()->RecordEvalCall();
+          scope_->DeclarationScope()->RecordEvalCall();
         }
         result = factory()->NewCall(result, args, pos);
         if (fni_ != NULL) fni_->RemoveLastFunction();
         break;
       }
 
       case Token::PERIOD: {
         Consume(Token::PERIOD);
         int pos = position();
         Handle<String> name = ParseIdentifierName(CHECK_OK);
@@ skipping 163 matching lines @@
   //   ArrayLiteral
   //   ObjectLiteral
   //   RegExpLiteral
   //   '(' Expression ')'
 
   int pos = peek_position();
   Expression* result = NULL;
   switch (peek()) {
     case Token::THIS: {
       Consume(Token::THIS);
-      result = factory()->NewVariableProxy(top_scope_->receiver());
+      result = factory()->NewVariableProxy(scope_->receiver());
       break;
     }
 
     case Token::NULL_LITERAL:
       Consume(Token::NULL_LITERAL);
       result = factory()->NewLiteral(isolate()->factory()->null_value(), pos);
       break;
 
     case Token::TRUE_LITERAL:
       Consume(Token::TRUE_LITERAL);
@@ skipping 10 matching lines @@
     case Token::FUTURE_STRICT_RESERVED_WORD: {
       // Using eval or arguments in this context is OK even in strict mode.
       Handle<String> name = ParseIdentifier(kAllowEvalOrArguments, CHECK_OK);
       if (fni_ != NULL) fni_->PushVariableName(name);
       // The name may refer to a module instance object, so its type is unknown.
 #ifdef DEBUG
       if (FLAG_print_interface_details)
         PrintF("# Variable %s ", name->ToAsciiArray());
 #endif
       Interface* interface = Interface::NewUnknown(zone());
-      result = top_scope_->NewUnresolved(factory(), name, interface, pos);
+      result = scope_->NewUnresolved(factory(), name, interface, pos);
       break;
     }
 
     case Token::NUMBER: {
       Consume(Token::NUMBER);
       ASSERT(scanner().is_literal_ascii());
       double value = StringToDouble(isolate()->unicode_cache(),
                                     scanner().literal_ascii_string(),
                                     ALLOW_HEX | ALLOW_OCTAL |
                                         ALLOW_IMPLICIT_OCTAL | ALLOW_BINARY);
@@ skipping 69 matching lines @@
       elem = ParseAssignmentExpression(true, CHECK_OK);
     }
     values->Add(elem, zone());
     if (peek() != Token::RBRACK) {
       Expect(Token::COMMA, CHECK_OK);
     }
   }
   Expect(Token::RBRACK, CHECK_OK);
 
   // Update the scope information before the pre-parsing bailout.
-  int literal_index = current_function_state_->NextMaterializedLiteralIndex();
+  int literal_index = function_state_->NextMaterializedLiteralIndex();
 
   return factory()->NewArrayLiteral(values, literal_index, pos);
 }
 
 
 bool CompileTimeValue::IsCompileTimeValue(Expression* expression) {
   if (expression->AsLiteral() != NULL) return true;
   MaterializedLiteral* lit = expression->AsMaterializedLiteral();
   return lit != NULL && lit->is_simple();
 }
@@ skipping 41 matching lines @@
   //       ((IdentifierName | String | Number) ':' AssignmentExpression)
   //     | (('get' | 'set') (IdentifierName | String | Number) FunctionLiteral)
   //    )*[','] '}'
 
   int pos = peek_position();
   ZoneList<ObjectLiteral::Property*>* properties =
       new(zone()) ZoneList<ObjectLiteral::Property*>(4, zone());
   int number_of_boilerplate_properties = 0;
   bool has_function = false;
 
-  ObjectLiteralChecker checker(this, top_scope_->language_mode());
+  ObjectLiteralChecker checker(this, scope_->language_mode());
 
   Expect(Token::LBRACE, CHECK_OK);
 
   while (peek() != Token::RBRACE) {
     if (fni_ != NULL) fni_->Enter();
 
     Literal* key = NULL;
     Token::Value next = peek();
     int next_pos = peek_position();
 
@@ skipping 100 matching lines @@
 
     Expect(Token::COLON, CHECK_OK);
     Expression* value = ParseAssignmentExpression(true, CHECK_OK);
 
     ObjectLiteral::Property* property =
         factory()->NewObjectLiteralProperty(key, value);
 
     // Mark top-level object literals that contain function literals and
     // pretenure the literal so it can be added as a constant function
     // property.
-    if (top_scope_->DeclarationScope()->is_global_scope() &&
+    if (scope_->DeclarationScope()->is_global_scope() &&
         value->AsFunctionLiteral() != NULL) {
       has_function = true;
       value->AsFunctionLiteral()->set_pretenure();
     }
 
     // Count CONSTANT or COMPUTED properties to maintain the enumeration order.
     if (ObjectLiteral::IsBoilerplateProperty(property)) {
       number_of_boilerplate_properties++;
     }
     properties->Add(property, zone());
 
     // TODO(1240767): Consider allowing trailing comma.
     if (peek() != Token::RBRACE) Expect(Token::COMMA, CHECK_OK);
 
     if (fni_ != NULL) {
       fni_->Infer();
       fni_->Leave();
     }
   }
   Expect(Token::RBRACE, CHECK_OK);
 
   // Computation of literal_index must happen before pre parse bailout.
-  int literal_index = current_function_state_->NextMaterializedLiteralIndex();
+  int literal_index = function_state_->NextMaterializedLiteralIndex();
 
   return factory()->NewObjectLiteral(properties,
                                      literal_index,
                                      number_of_boilerplate_properties,
                                      has_function,
                                      pos);
 }
 
 
 ZoneList<Expression*>* Parser::ParseArguments(bool* ok) {
@@ skipping 157 matching lines @@
   // either information available directly, especially not when lazily compiling
   // a function like 'g'. We hence rely on the following invariants:
   // - (1) is the case iff the innermost scope of the deserialized scope chain
   //   under which we compile is _not_ a declaration scope. This holds because
   //   in all normal cases, function declarations are fully hoisted to a
   //   declaration scope and compiled relative to that.
   // - (2) is the case iff the current declaration scope is still the original
   //   one relative to the deserialized scope chain. Otherwise we must be
   //   compiling a function in an inner declaration scope in the eval, e.g. a
   //   nested function, and hoisting works normally relative to that.
-  Scope* declaration_scope = top_scope_->DeclarationScope();
+  Scope* declaration_scope = scope_->DeclarationScope();
   Scope* original_declaration_scope = original_scope_->DeclarationScope();
   Scope* scope =
       function_type == FunctionLiteral::DECLARATION && !is_extended_mode() &&
       (original_scope_ == original_declaration_scope ||
        declaration_scope != original_declaration_scope)
           ? NewScope(declaration_scope, FUNCTION_SCOPE)
-          : NewScope(top_scope_, FUNCTION_SCOPE);
+          : NewScope(scope_, FUNCTION_SCOPE);
   ZoneList<Statement*>* body = NULL;
   int materialized_literal_count = -1;
   int expected_property_count = -1;
   int handler_count = 0;
   FunctionLiteral::ParameterFlag duplicate_parameters =
       FunctionLiteral::kNoDuplicateParameters;
   FunctionLiteral::IsParenthesizedFlag parenthesized = parenthesized_function_
       ? FunctionLiteral::kIsParenthesized
       : FunctionLiteral::kNotParenthesized;
   FunctionLiteral::IsGeneratorFlag generator = is_generator
       ? FunctionLiteral::kIsGenerator
       : FunctionLiteral::kNotGenerator;
   DeferredFeedbackSlotProcessor* slot_processor;
   AstProperties ast_properties;
   BailoutReason dont_optimize_reason = kNoReason;
   // Parse function body.
-  { FunctionState function_state(this, scope);
-    top_scope_->SetScopeName(function_name);
+  { FunctionState function_state(&function_state_, &scope_, scope, zone());
+    scope_->SetScopeName(function_name);
 
     if (is_generator) {
       // For generators, allocating variables in contexts is currently a win
       // because it minimizes the work needed to suspend and resume an
       // activation.
-      top_scope_->ForceContextAllocation();
+      scope_->ForceContextAllocation();
 
       // Calling a generator returns a generator object.  That object is stored
       // in a temporary variable, a definition that is used by "yield"
       // expressions.  Presence of a variable for the generator object in the
       // FunctionState indicates that this function is a generator.
-      Variable* temp = top_scope_->DeclarationScope()->NewTemporary(
+      Variable* temp = scope_->DeclarationScope()->NewTemporary(
           isolate()->factory()->dot_generator_object_string());
       function_state.set_generator_object_variable(temp);
     }
 
     //  FormalParameterList ::
     //    '(' (Identifier)*[','] ')'
     Expect(Token::LPAREN, CHECK_OK);
     scope->set_start_position(scanner().location().beg_pos);
 
     // We don't yet know if the function will be strict, so we cannot yet
     // produce errors for parameter names or duplicates. However, we remember
     // the locations of these errors if they occur and produce the errors later.
     Scanner::Location eval_args_error_log = Scanner::Location::invalid();
     Scanner::Location dupe_error_loc = Scanner::Location::invalid();
     Scanner::Location reserved_loc = Scanner::Location::invalid();
 
     bool done = (peek() == Token::RPAREN);
     while (!done) {
       bool is_strict_reserved = false;
       Handle<String> param_name =
           ParseIdentifierOrStrictReservedWord(&is_strict_reserved, CHECK_OK);
 
       // Store locations for possible future error reports.
       if (!eval_args_error_log.IsValid() && IsEvalOrArguments(param_name)) {
         eval_args_error_log = scanner().location();
       }
       if (!reserved_loc.IsValid() && is_strict_reserved) {
         reserved_loc = scanner().location();
       }
-      if (!dupe_error_loc.IsValid() && top_scope_->IsDeclared(param_name)) {
+      if (!dupe_error_loc.IsValid() && scope_->IsDeclared(param_name)) {
         duplicate_parameters = FunctionLiteral::kHasDuplicateParameters;
         dupe_error_loc = scanner().location();
       }
 
-      top_scope_->DeclareParameter(param_name, VAR);
+      scope_->DeclareParameter(param_name, VAR);
       num_parameters++;
       if (num_parameters > Code::kMaxArguments) {
         ReportMessageAt(scanner().location(), "too_many_parameters");
         *ok = false;
         return NULL;
       }
       done = (peek() == Token::RPAREN);
       if (!done) Expect(Token::COMMA, CHECK_OK);
     }
     Expect(Token::RPAREN, CHECK_OK);
 
     Expect(Token::LBRACE, CHECK_OK);
 
     // If we have a named function expression, we add a local variable
     // declaration to the body of the function with the name of the
     // function and let it refer to the function itself (closure).
     // NOTE: We create a proxy and resolve it here so that in the
     // future we can change the AST to only refer to VariableProxies
     // instead of Variables and Proxis as is the case now.
     Variable* fvar = NULL;
     Token::Value fvar_init_op = Token::INIT_CONST;
     if (function_type == FunctionLiteral::NAMED_EXPRESSION) {
       if (is_extended_mode()) fvar_init_op = Token::INIT_CONST_HARMONY;
       VariableMode fvar_mode = is_extended_mode() ? CONST_HARMONY : CONST;
-      fvar = new(zone()) Variable(top_scope_,
+      fvar = new(zone()) Variable(scope_,
          function_name, fvar_mode, true /* is valid LHS */,
          Variable::NORMAL, kCreatedInitialized, Interface::NewConst());
       VariableProxy* proxy = factory()->NewVariableProxy(fvar);
       VariableDeclaration* fvar_declaration = factory()->NewVariableDeclaration(
-          proxy, fvar_mode, top_scope_, RelocInfo::kNoPosition);
-      top_scope_->DeclareFunctionVar(fvar_declaration);
+          proxy, fvar_mode, scope_, RelocInfo::kNoPosition);
+      scope_->DeclareFunctionVar(fvar_declaration);
     }
 
     // Determine whether the function will be lazily compiled.
     // The heuristics are:
     // - It must not have been prohibited by the caller to Parse (some callers
     //   need a full AST).
     // - The outer scope must allow lazy compilation of inner functions.
     // - The function mustn't be a function expression with an open parenthesis
     //   before; we consider that a hint that the function will be called
     //   immediately, and it would be a waste of time to make it lazily
     //   compiled.
     // These are all things we can know at this point, without looking at the
     // function itself.
     bool is_lazily_compiled = (mode() == PARSE_LAZILY &&
-                               top_scope_->AllowsLazyCompilation() &&
+                               scope_->AllowsLazyCompilation() &&
                                !parenthesized_function_);
     parenthesized_function_ = false;  // The bit was set for this function only.
 
     if (is_lazily_compiled) {
       int function_block_pos = position();
       FunctionEntry entry;
       if (pre_parse_data_ != NULL) {
         // If we have pre_parse_data_, we use it to skip parsing the function
         // body.  The preparser data contains the information we need to
         // construct the lazy function.
         entry = pre_parse_data()->GetFunctionEntry(function_block_pos);
         if (entry.is_valid()) {
           if (entry.end_pos() <= function_block_pos) {
             // End position greater than end of stream is safe, and hard
             // to check.
             ReportInvalidPreparseData(function_name, CHECK_OK);
           }
           scanner().SeekForward(entry.end_pos() - 1);
 
           scope->set_end_position(entry.end_pos());
           Expect(Token::RBRACE, CHECK_OK);
           isolate()->counters()->total_preparse_skipped()->Increment(
               scope->end_position() - function_block_pos);
           materialized_literal_count = entry.literal_count();
           expected_property_count = entry.property_count();
-          top_scope_->SetLanguageMode(entry.language_mode());
+          scope_->SetLanguageMode(entry.language_mode());
         } else {
           is_lazily_compiled = false;
         }
       } else {
         // With no preparser data, we partially parse the function, without
         // building an AST. This gathers the data needed to build a lazy
         // function.
         SingletonLogger logger;
         PreParser::PreParseResult result = LazyParseFunctionLiteral(&logger);
         if (result == PreParser::kPreParseStackOverflow) {
@@ skipping 14 matching lines @@
               args);
           *ok = false;
           return NULL;
         }
         scope->set_end_position(logger.end());
         Expect(Token::RBRACE, CHECK_OK);
         isolate()->counters()->total_preparse_skipped()->Increment(
             scope->end_position() - function_block_pos);
         materialized_literal_count = logger.literals();
         expected_property_count = logger.properties();
-        top_scope_->SetLanguageMode(logger.language_mode());
+        scope_->SetLanguageMode(logger.language_mode());
       }
     }
 
     if (!is_lazily_compiled) {
       ParsingModeScope parsing_mode(this, PARSE_EAGERLY);
       body = new(zone()) ZoneList<Statement*>(8, zone());
       if (fvar != NULL) {
-        VariableProxy* fproxy = top_scope_->NewUnresolved(
+        VariableProxy* fproxy = scope_->NewUnresolved(
             factory(), function_name, Interface::NewConst());
         fproxy->BindTo(fvar);
         body->Add(factory()->NewExpressionStatement(
             factory()->NewAssignment(fvar_init_op,
                                      fproxy,
                                      factory()->NewThisFunction(pos),
                                      RelocInfo::kNoPosition),
             RelocInfo::kNoPosition), zone());
       }
 
       // For generators, allocate and yield an iterator on function entry.
       if (is_generator) {
         ZoneList<Expression*>* arguments =
             new(zone()) ZoneList<Expression*>(0, zone());
         CallRuntime* allocation = factory()->NewCallRuntime(
             isolate()->factory()->empty_string(),
             Runtime::FunctionForId(Runtime::kCreateJSGeneratorObject),
             arguments, pos);
         VariableProxy* init_proxy = factory()->NewVariableProxy(
-            current_function_state_->generator_object_variable());
+            function_state_->generator_object_variable());
         Assignment* assignment = factory()->NewAssignment(
             Token::INIT_VAR, init_proxy, allocation, RelocInfo::kNoPosition);
         VariableProxy* get_proxy = factory()->NewVariableProxy(
-            current_function_state_->generator_object_variable());
+            function_state_->generator_object_variable());
         Yield* yield = factory()->NewYield(
             get_proxy, assignment, Yield::INITIAL, RelocInfo::kNoPosition);
         body->Add(factory()->NewExpressionStatement(
             yield, RelocInfo::kNoPosition), zone());
       }
 
       ParseSourceElements(body, Token::RBRACE, false, false, CHECK_OK);
 
       if (is_generator) {
         VariableProxy* get_proxy = factory()->NewVariableProxy(
-            current_function_state_->generator_object_variable());
+            function_state_->generator_object_variable());
         Expression *undefined = factory()->NewLiteral(
             isolate()->factory()->undefined_value(), RelocInfo::kNoPosition);
         Yield* yield = factory()->NewYield(
             get_proxy, undefined, Yield::FINAL, RelocInfo::kNoPosition);
         body->Add(factory()->NewExpressionStatement(
             yield, RelocInfo::kNoPosition), zone());
       }
 
       materialized_literal_count = function_state.materialized_literal_count();
       expected_property_count = function_state.expected_property_count();
       handler_count = function_state.handler_count();
 
       Expect(Token::RBRACE, CHECK_OK);
       scope->set_end_position(scanner().location().end_pos);
     }
 
     // Validate strict mode. We can do this only after parsing the function,
     // since the function can declare itself strict.
-    if (!top_scope_->is_classic_mode()) {
+    if (!scope_->is_classic_mode()) {
       if (IsEvalOrArguments(function_name)) {
         ReportMessageAt(function_name_location, "strict_eval_arguments");
         *ok = false;
         return NULL;
       }
       if (name_is_strict_reserved) {
         ReportMessageAt(function_name_location, "unexpected_strict_reserved");
         *ok = false;
         return NULL;
       }
@@ skipping 60 matching lines @@
     reusable_preparser_->set_allow_harmony_scoping(allow_harmony_scoping());
     reusable_preparser_->set_allow_modules(allow_modules());
     reusable_preparser_->set_allow_natives_syntax(allow_natives_syntax());
     reusable_preparser_->set_allow_lazy(true);
     reusable_preparser_->set_allow_generators(allow_generators());
     reusable_preparser_->set_allow_for_of(allow_for_of());
     reusable_preparser_->set_allow_harmony_numeric_literals(
         allow_harmony_numeric_literals());
   }
   PreParser::PreParseResult result =
-      reusable_preparser_->PreParseLazyFunction(top_scope_->language_mode(),
+      reusable_preparser_->PreParseLazyFunction(scope_->language_mode(),
                                                 is_generator(),
                                                 logger);
   return result;
 }
 
 
 Expression* Parser::ParseV8Intrinsic(bool* ok) {
   // CallRuntime ::
   //   '%' Identifier Arguments
 
   int pos = peek_position();
   Expect(Token::MOD, CHECK_OK);
   // Allow "eval" or "arguments" for backward compatibility.
   Handle<String> name = ParseIdentifier(kAllowEvalOrArguments, CHECK_OK);
   ZoneList<Expression*>* args = ParseArguments(CHECK_OK);
 
   if (extension_ != NULL) {
     // The extension structures are only accessible while parsing the
     // very first time not when reparsing because of lazy compilation.
-    top_scope_->DeclarationScope()->ForceEagerCompilation();
+    scope_->DeclarationScope()->ForceEagerCompilation();
   }
 
   const Runtime::Function* function = Runtime::FunctionForName(name);
 
   // Check for built-in IS_VAR macro.
   if (function != NULL &&
       function->intrinsic_type == Runtime::RUNTIME &&
       function->function_id == Runtime::kIS_VAR) {
     // %IS_VAR(x) evaluates to x if x is a variable,
     // leads to a parse error otherwise.  Could be implemented as an
@@ skipping 47 matching lines @@
       : NULL;
 
   if (proxy != NULL) proxy->MarkAsLValue();
 }
 
 
 // Checks LHS expression for assignment and prefix/postfix increment/decrement
 // in strict mode.
 void Parser::CheckStrictModeLValue(Expression* expression,
                                    bool* ok) {
-  ASSERT(!top_scope_->is_classic_mode());
+  ASSERT(!scope_->is_classic_mode());
   VariableProxy* lhs = expression != NULL
       ? expression->AsVariableProxy()
       : NULL;
 
   if (lhs != NULL && !lhs->is_this() && IsEvalOrArguments(lhs->name())) {
     ReportMessage("strict_eval_arguments", Vector<const char*>::empty());
     *ok = false;
   }
 }
 
@@ skipping 1074 matching lines @@
       ASSERT(info()->isolate()->has_pending_exception());
     } else {
       result = ParseProgram();
     }
   }
   info()->SetFunction(result);
   return (result != NULL);
 }
 
 } }  // namespace v8::internal