Merge TemporaryScope with LexicalScope.

src/parser.cc

 // Copyright 2010 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 228 matching lines @@
   } else {
     // Only call immediately after adding an atom or character!
     UNREACHABLE();
     return;
   }
   terms_.Add(new RegExpQuantifier(min, max, type, atom));
   LAST(ADD_TERM);
 }
 
 
-// A temporary scope stores information during parsing, just like
-// a plain scope.  However, temporary scopes are not kept around
-// after parsing or referenced by syntax trees so they can be stack-
-// allocated and hence used by the pre-parser.
-class TemporaryScope BASE_EMBEDDED {
- public:
-  explicit TemporaryScope(TemporaryScope** variable);
-  ~TemporaryScope();
-
-  int NextMaterializedLiteralIndex() {
-    int next_index =
-        materialized_literal_count_ + JSFunction::kLiteralsPrefixSize;
-    materialized_literal_count_++;
-    return next_index;
-  }
-  int materialized_literal_count() { return materialized_literal_count_; }
-
-  void SetThisPropertyAssignmentInfo(
-      bool only_simple_this_property_assignments,
-      Handle<FixedArray> this_property_assignments) {
-    only_simple_this_property_assignments_ =
-        only_simple_this_property_assignments;
-    this_property_assignments_ = this_property_assignments;
-  }
-  bool only_simple_this_property_assignments() {
-    return only_simple_this_property_assignments_;
-  }
-  Handle<FixedArray> this_property_assignments() {
-    return this_property_assignments_;
-  }
-
-  void AddProperty() { expected_property_count_++; }
-  int expected_property_count() { return expected_property_count_; }
-
-  void AddLoop() { loop_count_++; }
-  bool ContainsLoops() const { return loop_count_ > 0; }
-
- private:
-  // Captures the number of literals that need materialization in the
-  // function.  Includes regexp literals, and boilerplate for object
-  // and array literals.
-  int materialized_literal_count_;
-
-  // Properties count estimation.
-  int expected_property_count_;
-
-  // Keeps track of assignments to properties of this. Used for
-  // optimizing constructors.
-  bool only_simple_this_property_assignments_;
-  Handle<FixedArray> this_property_assignments_;
-
-  // Captures the number of loops inside the scope.
-  int loop_count_;
-
-  // Bookkeeping
-  TemporaryScope** variable_;
-  TemporaryScope* parent_;
-};
-
-
-TemporaryScope::TemporaryScope(TemporaryScope** variable)
-  : materialized_literal_count_(0),
-    expected_property_count_(0),
-    only_simple_this_property_assignments_(false),
-    this_property_assignments_(
-        Isolate::Current()->factory()->empty_fixed_array()),
-    loop_count_(0),
-    variable_(variable),
-    parent_(*variable) {
-  *variable = this;
-}
-
-
-TemporaryScope::~TemporaryScope() {
-  *variable_ = parent_;
-}
-
-
 Handle<String> Parser::LookupSymbol(int symbol_id) {
   // Length of symbol cache is the number of identified symbols.
   // If we are larger than that, or negative, it's not a cached symbol.
   // This might also happen if there is no preparser symbol data, even
   // if there is some preparser data.
   if (static_cast<unsigned>(symbol_id)
       >= static_cast<unsigned>(symbol_cache_.length())) {
     if (scanner().is_literal_ascii()) {
       return isolate()->factory()->LookupAsciiSymbol(
           scanner().literal_ascii_string());
@@ skipping 195 matching lines @@
  private:
   Target** variable_;
   Target* previous_;
 };
 
 
 // ----------------------------------------------------------------------------
 // LexicalScope is a support class to facilitate manipulation of the
 // Parser's scope stack. The constructor sets the parser's top scope
 // to the incoming scope, and the destructor resets it.
+//
+// Additionlaly, it stores transient information used during parsing.
+// These scopes are not kept around after parsing or referenced by syntax
+// trees so they can be stack-allocated and hence used by the pre-parser.
 
 class LexicalScope BASE_EMBEDDED {
  public:
-  LexicalScope(Scope** scope_variable,
-               int* with_nesting_level_variable,
-               Scope* scope)
-    : scope_variable_(scope_variable),
-      with_nesting_level_variable_(with_nesting_level_variable),
-      prev_scope_(*scope_variable),
-      prev_level_(*with_nesting_level_variable) {
-    *scope_variable = scope;
-    *with_nesting_level_variable = 0;
+  LexicalScope(Parser* parser, Scope* scope);
+  ~LexicalScope();
+
+  int NextMaterializedLiteralIndex() {
+    int next_index =
+        materialized_literal_count_ + JSFunction::kLiteralsPrefixSize;
+    materialized_literal_count_++;
+    return next_index;
+  }
+  int materialized_literal_count() { return materialized_literal_count_; }
+
+  void SetThisPropertyAssignmentInfo(
+      bool only_simple_this_property_assignments,
+      Handle<FixedArray> this_property_assignments) {
+    only_simple_this_property_assignments_ =
+        only_simple_this_property_assignments;
+    this_property_assignments_ = this_property_assignments;
+  }
+  bool only_simple_this_property_assignments() {
+    return only_simple_this_property_assignments_;
+  }
+  Handle<FixedArray> this_property_assignments() {
+    return this_property_assignments_;
   }
 
-  ~LexicalScope() {
-    (*scope_variable_)->Leave();
-    *scope_variable_ = prev_scope_;
-    *with_nesting_level_variable_ = prev_level_;
-  }
+  void AddProperty() { expected_property_count_++; }
+  int expected_property_count() { return expected_property_count_; }
+
+  void AddLoop() { loop_count_++; }
+  bool ContainsLoops() const { return loop_count_ > 0; }
 
  private:
-  Scope** scope_variable_;
-  int* with_nesting_level_variable_;
-  Scope* prev_scope_;
-  int prev_level_;
+  // Captures the number of literals that need materialization in the
+  // function.  Includes regexp literals, and boilerplate for object
+  // and array literals.
+  int materialized_literal_count_;
+
+  // Properties count estimation.
+  int expected_property_count_;
+
+  // Keeps track of assignments to properties of this. Used for
+  // optimizing constructors.
+  bool only_simple_this_property_assignments_;
+  Handle<FixedArray> this_property_assignments_;
+
+  // Captures the number of loops inside the scope.
+  int loop_count_;
+
+  // Bookkeeping
+  Parser* parser_;
+  // Previous values
+  LexicalScope* lexical_scope_parent_;
+  Scope* previous_scope_;
+  int previous_with_nesting_level_;
 };
 
+
+LexicalScope::LexicalScope(Parser* parser, Scope* scope)
+  : materialized_literal_count_(0),
+    expected_property_count_(0),
+    only_simple_this_property_assignments_(false),
+    this_property_assignments_(
+        Isolate::Current()->factory()->empty_fixed_array()),
+    loop_count_(0),
+    parser_(parser),
+    lexical_scope_parent_(parser->lexical_scope_),
+    previous_scope_(parser->top_scope_),
+    previous_with_nesting_level_(parser->with_nesting_level_) {
+  parser->top_scope_ = scope;
+  parser->lexical_scope_ = this;
+  parser->with_nesting_level_ = 0;
+}
+
+
+LexicalScope::~LexicalScope() {
+  parser_->top_scope_->Leave();
+  parser_->top_scope_ = previous_scope_;
+  parser_->lexical_scope_ = lexical_scope_parent_;
+  parser_->with_nesting_level_ = previous_with_nesting_level_;
+}
+
+
 // ----------------------------------------------------------------------------
 // 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; \
@@ skipping 13 matching lines @@
 Parser::Parser(Handle<Script> script,
                bool allow_natives_syntax,
                v8::Extension* extension,
                ScriptDataImpl* pre_data)
     : isolate_(script->GetIsolate()),
       symbol_cache_(pre_data ? pre_data->symbol_count() : 0),
       script_(script),
       scanner_(isolate_),
       top_scope_(NULL),
       with_nesting_level_(0),
-      temp_scope_(NULL),
+      lexical_scope_(NULL),
       target_stack_(NULL),
       allow_natives_syntax_(allow_natives_syntax),
       extension_(extension),
       pre_data_(pre_data),
       fni_(NULL),
       stack_overflow_(false),
       parenthesized_function_(false) {
   AstNode::ResetIds();
 }
 
@@ skipping 37 matching lines @@
   if (allow_natives_syntax_ || extension_ != NULL) mode_ = PARSE_EAGERLY;
 
   Scope::Type type =
     in_global_context
       ? Scope::GLOBAL_SCOPE
       : Scope::EVAL_SCOPE;
   Handle<String> no_name = isolate()->factory()->empty_symbol();
 
   FunctionLiteral* result = NULL;
   { Scope* scope = NewScope(top_scope_, type, inside_with());
-    LexicalScope lexical_scope(&this->top_scope_, &this->with_nesting_level_,
-                               scope);
-    TemporaryScope temp_scope(&this->temp_scope_);
+    LexicalScope lexical_scope(this, scope);
     if (strict_mode == kStrictMode) {
       top_scope_->EnableStrictMode();
     }
     ZoneList<Statement*>* body = new ZoneList<Statement*>(16);
     bool ok = true;
     int beg_loc = scanner().location().beg_pos;
     ParseSourceElements(body, Token::EOS, &ok);
     if (ok && top_scope_->is_strict_mode()) {
       CheckOctalLiteral(beg_loc, scanner().location().end_pos, &ok);
     }
     if (ok) {
       result = new FunctionLiteral(
           no_name,
           top_scope_,
           body,
-          temp_scope.materialized_literal_count(),
-          temp_scope.expected_property_count(),
-          temp_scope.only_simple_this_property_assignments(),
-          temp_scope.this_property_assignments(),
+          lexical_scope.materialized_literal_count(),
+          lexical_scope.expected_property_count(),
+          lexical_scope.only_simple_this_property_assignments(),
+          lexical_scope.this_property_assignments(),
           0,
           0,
           source->length(),
           false,
-          temp_scope.ContainsLoops());
+          lexical_scope.ContainsLoops());
     } else if (stack_overflow_) {
       isolate()->StackOverflow();
     }
   }
 
   // Make sure the target stack is empty.
   ASSERT(target_stack_ == NULL);
 
   // If there was a syntax error we have to get rid of the AST
   // and it is not safe to do so before the scope has been deleted.
@@ skipping 43 matching lines @@
   // Place holder for the result.
   FunctionLiteral* result = NULL;
 
   {
     // Parse the function literal.
     Handle<String> no_name = isolate()->factory()->empty_symbol();
     Scope* scope = NewScope(top_scope_, Scope::GLOBAL_SCOPE, inside_with());
     if (!info->closure().is_null()) {
       scope = Scope::DeserializeScopeChain(info, scope);
     }
-    LexicalScope lexical_scope(&this->top_scope_, &this->with_nesting_level_,
-                               scope);
-    TemporaryScope temp_scope(&this->temp_scope_);
+    LexicalScope lexical_scope(this, scope);
 
     if (shared_info->strict_mode()) {
       top_scope_->EnableStrictMode();
     }
 
     FunctionLiteralType type =
         shared_info->is_expression() ? EXPRESSION : DECLARATION;
     bool ok = true;
     result = ParseFunctionLiteral(name,
                                   false,    // Strict mode name already checked.
@@ skipping 404 matching lines @@
     }
     processor->Add(stat);
   }
 
   // Propagate the collected information on this property assignments.
   if (top_scope_->is_function_scope()) {
     bool only_simple_this_property_assignments =
         this_property_assignment_finder.only_simple_this_property_assignments()
         && top_scope_->declarations()->length() == 0;
     if (only_simple_this_property_assignments) {
-      temp_scope_->SetThisPropertyAssignmentInfo(
+      lexical_scope_->SetThisPropertyAssignmentInfo(
           only_simple_this_property_assignments,
           this_property_assignment_finder.GetThisPropertyAssignments());
     }
   }
   return 0;
 }
 
 
 Statement* Parser::ParseStatement(ZoneStringList* labels, bool* ok) {
   // Statement ::
@@ skipping 976 matching lines @@
 
   return result;
 }
 
 
 DoWhileStatement* Parser::ParseDoWhileStatement(ZoneStringList* labels,
                                                 bool* ok) {
   // DoStatement ::
   //   'do' Statement 'while' '(' Expression ')' ';'
 
-  temp_scope_->AddLoop();
+  lexical_scope_->AddLoop();
   DoWhileStatement* loop = new DoWhileStatement(labels);
   Target target(&this->target_stack_, loop);
 
   Expect(Token::DO, CHECK_OK);
   Statement* body = ParseStatement(NULL, CHECK_OK);
   Expect(Token::WHILE, CHECK_OK);
   Expect(Token::LPAREN, CHECK_OK);
 
   if (loop != NULL) {
     int position = scanner().location().beg_pos;
@@ skipping 12 matching lines @@
 
   if (loop != NULL) loop->Initialize(cond, body);
   return loop;
 }
 
 
 WhileStatement* Parser::ParseWhileStatement(ZoneStringList* labels, bool* ok) {
   // WhileStatement ::
   //   'while' '(' Expression ')' Statement
 
-  temp_scope_->AddLoop();
+  lexical_scope_->AddLoop();
   WhileStatement* loop = new WhileStatement(labels);
   Target target(&this->target_stack_, loop);
 
   Expect(Token::WHILE, CHECK_OK);
   Expect(Token::LPAREN, CHECK_OK);
   Expression* cond = ParseExpression(true, CHECK_OK);
   if (cond != NULL) cond->set_is_loop_condition(true);
   Expect(Token::RPAREN, CHECK_OK);
   Statement* body = ParseStatement(NULL, CHECK_OK);
 
   if (loop != NULL) loop->Initialize(cond, body);
   return loop;
 }
 
 
 Statement* Parser::ParseForStatement(ZoneStringList* labels, bool* ok) {
   // ForStatement ::
   //   'for' '(' Expression? ';' Expression? ';' Expression? ')' Statement
 
-  temp_scope_->AddLoop();
+  lexical_scope_->AddLoop();
   Statement* init = NULL;
 
   Expect(Token::FOR, CHECK_OK);
   Expect(Token::LPAREN, CHECK_OK);
   if (peek() != Token::SEMICOLON) {
     if (peek() == Token::VAR || peek() == Token::CONST) {
       Expression* each = NULL;
       Block* variable_statement =
           ParseVariableDeclarations(false, &each, CHECK_OK);
       if (peek() == Token::IN && each != NULL) {
@@ skipping 126 matching lines @@
   // 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()) {
-    temp_scope_->AddProperty();
+    lexical_scope_->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(true);
   }
 
   if (fni_ != NULL) {
     // Check if the right hand side is a call to avoid inferring a
@@ skipping 621 matching lines @@
       elem = ParseAssignmentExpression(true, CHECK_OK);
     }
     values->Add(elem);
     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 = temp_scope_->NextMaterializedLiteralIndex();
+  int literal_index = lexical_scope_->NextMaterializedLiteralIndex();
 
   // Allocate a fixed array with all the literals.
   Handle<FixedArray> literals =
       isolate()->factory()->NewFixedArray(values->length(), TENURED);
 
   // Fill in the literals.
   bool is_simple = true;
   int depth = 1;
   for (int i = 0, n = values->length(); i < n; i++) {
     MaterializedLiteral* m_literal = values->at(i)->AsMaterializedLiteral();
@@ skipping 411 matching lines @@
     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 = temp_scope_->NextMaterializedLiteralIndex();
+  int literal_index = lexical_scope_->NextMaterializedLiteralIndex();
 
   Handle<FixedArray> constant_properties = isolate()->factory()->NewFixedArray(
       number_of_boilerplate_properties * 2, TENURED);
 
   bool is_simple = true;
   bool fast_elements = true;
   int depth = 1;
   BuildObjectLiteralConstantProperties(properties,
                                        constant_properties,
                                        &is_simple,
                                        &fast_elements,
                                        &depth);
   return new ObjectLiteral(constant_properties,
                            properties,
                            literal_index,
                            is_simple,
                            fast_elements,
                            depth);
 }
 
 
 Expression* Parser::ParseRegExpLiteral(bool seen_equal, bool* ok) {
   if (!scanner().ScanRegExpPattern(seen_equal)) {
     Next();
     ReportMessage("unterminated_regexp", Vector<const char*>::empty());
     *ok = false;
     return NULL;
   }
 
-  int literal_index = temp_scope_->NextMaterializedLiteralIndex();
+  int literal_index = lexical_scope_->NextMaterializedLiteralIndex();
 
   Handle<String> js_pattern = NextLiteralString(TENURED);
   scanner().ScanRegExpFlags();
   Handle<String> js_flags = NextLiteralString(TENURED);
   Next();
 
   return new RegExpLiteral(js_pattern, js_flags, literal_index);
 }
 
 
@@ skipping 33 matching lines @@
   // The function name, if any.
   Handle<String> function_name = isolate()->factory()->empty_symbol();
   if (is_named && (type == EXPRESSION || type == NESTED)) {
     function_name = name;
   }
 
   int num_parameters = 0;
   // Parse function body.
   { Scope* scope =
         NewScope(top_scope_, Scope::FUNCTION_SCOPE, inside_with());
-    LexicalScope lexical_scope(&this->top_scope_, &this->with_nesting_level_,
-                               scope);
-    TemporaryScope temp_scope(&this->temp_scope_);
+    LexicalScope lexical_scope(this, scope);
     top_scope_->SetScopeName(name);
 
     //  FormalParameterList ::
     //    '(' (Identifier)*[','] ')'
     Expect(Token::LPAREN, CHECK_OK);
     int start_pos = scanner().location().beg_pos;
     Scanner::Location name_loc = Scanner::NoLocation();
     Scanner::Location dupe_loc = Scanner::NoLocation();
     Scanner::Location reserved_loc = Scanner::NoLocation();
 
@@ skipping 77 matching lines @@
       // Seek to position just before terminal '}'.
       scanner().SeekForward(end_pos - 1);
       materialized_literal_count = entry.literal_count();
       expected_property_count = entry.property_count();
       only_simple_this_property_assignments = false;
       this_property_assignments = isolate()->factory()->empty_fixed_array();
       Expect(Token::RBRACE, CHECK_OK);
     } else {
       ParseSourceElements(body, Token::RBRACE, CHECK_OK);
 
-      materialized_literal_count = temp_scope.materialized_literal_count();
-      expected_property_count = temp_scope.expected_property_count();
+      materialized_literal_count = lexical_scope.materialized_literal_count();
+      expected_property_count = lexical_scope.expected_property_count();
       only_simple_this_property_assignments =
-          temp_scope.only_simple_this_property_assignments();
-      this_property_assignments = temp_scope.this_property_assignments();
+          lexical_scope.only_simple_this_property_assignments();
+      this_property_assignments = lexical_scope.this_property_assignments();
 
       Expect(Token::RBRACE, CHECK_OK);
       end_pos = scanner().location().end_pos;
     }
 
     // Validate strict mode.
     if (top_scope_->is_strict_mode()) {
       if (IsEvalOrArguments(name)) {
         int position = function_token_position != RelocInfo::kNoPosition
             ? function_token_position
@@ skipping 40 matching lines @@
                             top_scope_,
                             body,
                             materialized_literal_count,
                             expected_property_count,
                             only_simple_this_property_assignments,
                             this_property_assignments,
                             num_parameters,
                             start_pos,
                             end_pos,
                             function_name->length() > 0,
-                            temp_scope.ContainsLoops());
+                            lexical_scope.ContainsLoops());
     function_literal->set_function_token_position(function_token_position);
 
     if (fni_ != NULL && !is_named) fni_->AddFunction(function_literal);
     return function_literal;
   }
 }
 
 
 Expression* Parser::ParseV8Intrinsic(bool* ok) {
   // CallRuntime ::
@@ skipping 1447 matching lines @@
                                    info->is_global(),
                                    info->StrictMode());
     }
   }
 
   info->SetFunction(result);
   return (result != NULL);
 }
 
 } }  // namespace v8::internal