Support lazy parsing of inner functions

src/preparser.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_PREPARSER_H
 #define V8_PREPARSER_H
 
 #include "src/v8.h"
 
 #include "src/bailout-reason.h"
 #include "src/func-name-inferrer.h"
 #include "src/hashmap.h"
 #include "src/scanner.h"
 #include "src/scopes.h"
 #include "src/token.h"
+#include "src/zone.h"
 
 namespace v8 {
 namespace internal {
 
 // Common base class shared between parser and pre-parser. Traits encapsulate
 // the differences between Parser and PreParser:
 
 // - Return types: For example, Parser functions return Expression* and
 // PreParser functions return PreParserExpression.
 
 // - Creating parse tree nodes: Parser generates an AST during the recursive
 // descent. PreParser doesn't create a tree. Instead, it passes around minimal
 // data objects (PreParserExpression, PreParserIdentifier etc.) which contain
 // just enough data for the upper layer functions. PreParserFactory is
 // responsible for creating these dummy objects. It provides a similar kind of
 // interface as AstNodeFactory, so ParserBase doesn't need to care which one is
 // used.
 
 // - Miscellaneous other tasks interleaved with the recursive descent. For
 // example, Parser keeps track of which function literals should be marked as
 // pretenured, and PreParser doesn't care.
 
 // The traits are expected to contain the following typedefs:
 // struct Traits {
 //   // In particular...
 //   struct Type {
 //     // Used by FunctionState and BlockState.
 //     typedef Scope;
 //     typedef GeneratorVariable;
-//     typedef Zone;
 //     // Return types for traversing functions.
 //     typedef Identifier;
 //     typedef Expression;
 //     typedef FunctionLiteral;
 //     typedef ClassLiteral;
 //     typedef ObjectLiteralProperty;
 //     typedef Literal;
 //     typedef ExpressionList;
 //     typedef PropertyList;
 //     // For constructing objects returned by the traversing functions.
 //     typedef Factory;
 //   };
 //   // ...
 // };
 
 template <typename Traits>
 class ParserBase : public Traits {
  public:
   // Shorten type names defined by Traits.
   typedef typename Traits::Type::Expression ExpressionT;
   typedef typename Traits::Type::Identifier IdentifierT;
   typedef typename Traits::Type::FunctionLiteral FunctionLiteralT;
   typedef typename Traits::Type::Literal LiteralT;
   typedef typename Traits::Type::ObjectLiteralProperty ObjectLiteralPropertyT;
 
   ParserBase(Scanner* scanner, uintptr_t stack_limit, v8::Extension* extension,
-             ParserRecorder* log, typename Traits::Type::Zone* zone,
+             ParserRecorder* log, Zone* zone,
              typename Traits::Type::Parser this_object)
       : Traits(this_object),
         parenthesized_function_(false),
         scope_(NULL),
         function_state_(NULL),
         extension_(extension),
         fni_(NULL),
         log_(log),
         mode_(PARSE_EAGERLY),  // Lazy mode must be set explicitly.
         stack_limit_(stack_limit),
@@ skipping 36 matching lines @@
   void set_allow_harmony_object_literals(bool allow) {
     allow_harmony_object_literals_ = allow;
   }
 
  protected:
   enum AllowEvalOrArgumentsAsIdentifier {
     kAllowEvalOrArguments,
     kDontAllowEvalOrArguments
   };
 
-  enum Mode {
-    PARSE_LAZILY,
-    PARSE_EAGERLY
-  };
+  enum Mode { PARSE_LAZILY, PARSE_EAGERLY, PARSE_INNER_FUNCTION_LAZILY };
 
   class Checkpoint;
   class ObjectLiteralChecker;
 
   // ---------------------------------------------------------------------------
   // FunctionState and BlockState together implement the parser's scope stack.
   // The parser's current scope is in scope_. 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 BlockState BASE_EMBEDDED {
@@ skipping 67 matching lines @@
     bool is_generator_;
     // For generators, this variable may hold the generator object. It variable
     // is used by yield expressions and return statements. It is not necessary
     // for generator functions to have this variable set.
     Variable* generator_object_variable_;
 
     FunctionState** function_state_stack_;
     FunctionState* outer_function_state_;
     typename Traits::Type::Scope** scope_stack_;
     typename Traits::Type::Scope* outer_scope_;
-    typename Traits::Type::Zone* extra_param_;
     typename Traits::Type::Factory* factory_;
 
     friend class ParserTraits;
     friend class Checkpoint;
   };
 
   // Annoyingly, arrow functions first parse as comma expressions, then when we
   // see the => we have to go back and reinterpret the arguments as being formal
   // parameters.  To do so we need to reset some of the parser state back to
   // what it was before the arguments were first seen.
@@ skipping 36 matching lines @@
     ParserBase* parser_;
     Mode old_mode_;
   };
 
   Scanner* scanner() const { return scanner_; }
   int position() { return scanner_->location().beg_pos; }
   int peek_position() { return scanner_->peek_location().beg_pos; }
   bool stack_overflow() const { return stack_overflow_; }
   void set_stack_overflow() { stack_overflow_ = true; }
   Mode mode() const { return mode_; }
-  typename Traits::Type::Zone* zone() const { return zone_; }
+  Zone* zone() const { return zone_; }
 
   INLINE(Token::Value peek()) {
     if (stack_overflow_) return Token::ILLEGAL;
     return scanner()->peek();
   }
 
   INLINE(Token::Value Next()) {
     if (stack_overflow_) return Token::ILLEGAL;
     {
       if (GetCurrentStackPosition() < stack_limit_) {
@@ skipping 281 matching lines @@
 
  private:
   Scanner* scanner_;
   bool stack_overflow_;
 
   bool allow_lazy_;
   bool allow_natives_syntax_;
   bool allow_arrow_functions_;
   bool allow_harmony_object_literals_;
 
-  typename Traits::Type::Zone* zone_;  // Only used by Parser.
+  Zone* zone_;
 };
 
 
 class PreParserIdentifier {
  public:
   PreParserIdentifier() : type_(kUnknownIdentifier) {}
   static PreParserIdentifier Default() {
     return PreParserIdentifier(kUnknownIdentifier);
   }
   static PreParserIdentifier Eval() {
@@ skipping 337 matching lines @@
  public:
   // These functions make list->Add(some_expression) work as no-ops.
   PreParserStatementList() {}
   PreParserStatementList* operator->() { return this; }
   void Add(PreParserStatement, void*) {}
 };
 
 
 class PreParserScope {
  public:
-  explicit PreParserScope(PreParserScope* outer_scope, ScopeType scope_type,
-                          void* = NULL)
-      : scope_type_(scope_type) {
+  PreParserScope(PreParserScope* outer_scope, ScopeType scope_type, Zone* zone,
+                 bool log_identifiers)
+      : outer_scope_(outer_scope),
+        scope_type_(scope_type),
+        zone_(zone),
+        declared_variables_(NULL),
+        unbound_variables_(NULL) {
     strict_mode_ = outer_scope ? outer_scope->strict_mode() : SLOPPY;
+    if (log_identifiers && is_declaration_scope()) {
+      ZoneAllocationPolicy allocator(zone);
+      declared_variables_ = new (zone->New(sizeof(ZoneHashMap)))
+          ZoneHashMap(ZoneHashMap::PointersMatch,
+                      ZoneHashMap::kDefaultHashMapCapacity, allocator);
+      unbound_variables_ = new (zone->New(sizeof(ZoneHashMap)))
+          ZoneHashMap(ZoneHashMap::PointersMatch,
+                      ZoneHashMap::kDefaultHashMapCapacity, allocator);
+    }
   }
 
+  ~PreParserScope();
+
   ScopeType type() { return scope_type_; }
   StrictMode strict_mode() const { return strict_mode_; }
   void SetStrictMode(StrictMode strict_mode) { strict_mode_ = strict_mode; }
   void SetScopeName(PreParserIdentifier name) {}
 
   // When PreParser is in use, lazy compilation is already being done,
   // things cannot get lazier than that.
   bool AllowsLazyCompilation() const { return false; }
 
   void set_start_position(int position) {}
   void set_end_position(int position) {}
 
   bool IsDeclared(const PreParserIdentifier& identifier) const { return false; }
   void DeclareParameter(const PreParserIdentifier& identifier, VariableMode) {}
   void RecordArgumentsUsage() {}
   void RecordThisUsage() {}
 
+  bool is_eval_scope() const { return scope_type_ == EVAL_SCOPE; }
+  bool is_function_scope() const {
+    return scope_type_ == FUNCTION_SCOPE || scope_type_ == ARROW_SCOPE;
+  }
+  bool is_module_scope() const { return scope_type_ == MODULE_SCOPE; }
+  bool is_global_scope() const { return scope_type_ == GLOBAL_SCOPE; }
+  bool is_declaration_scope() const {
+    return is_eval_scope() || is_function_scope() || is_module_scope() ||
+           is_global_scope();
+  }
+
+  // The scope immediately surrounding this scope, or NULL.
+  PreParserScope* outer_scope() const { return outer_scope_; }
+
+  // Walk up the scope chain and return the scope where var declarations will be
+  // hoisted to (could be this).
+  PreParserScope* DeclarationScope();
+
+  // Record a variable declaration in the current declaration scope
+  void Declare(const AstRawString* identifier);
+
+  // Record the usage of a variable in an identifier expression. If the variable
+  // was not declared in this scope, we report it to the full parser so it will
+  // be context-allocated.
+  void RecordVariableUsage(const AstRawString* identifier);
+
+  void LogUnboundVariables(ParserRecorder* recorder);
+
   // Allow scope->Foo() to work.
   PreParserScope* operator->() { return this; }
 
  private:
+  PreParserScope* outer_scope_;
   ScopeType scope_type_;
   StrictMode strict_mode_;
+  Zone* zone_;
+  ZoneHashMap* declared_variables_;
+  ZoneHashMap* unbound_variables_;
 };
 
 
 class PreParserFactory {
  public:
   explicit PreParserFactory(void* unused_value_factory) {}
   PreParserExpression NewStringLiteral(PreParserIdentifier identifier,
                                        int pos) {
     return PreParserExpression::Default();
   }
@@ skipping 128 matching lines @@
 
 class PreParserTraits {
  public:
   struct Type {
     // TODO(marja): To be removed. The Traits object should contain all the data
     // it needs.
     typedef PreParser* Parser;
 
     // Used by FunctionState and BlockState.
     typedef PreParserScope Scope;
-    typedef PreParserScope ScopePtr;
+    typedef PreParserScope ScopePtr;  // Return type of NewScope()
     inline static Scope* ptr_to_scope(ScopePtr& scope) { return &scope; }
 
     // PreParser doesn't need to store generator variables.
     typedef void GeneratorVariable;
-    // No interaction with Zones.
-    typedef void Zone;
 
     typedef int AstProperties;
     typedef Vector<PreParserIdentifier> ParameterIdentifierVector;
 
     // Return types for traversing functions.
     typedef PreParserIdentifier Identifier;
     typedef PreParserExpression Expression;
     typedef PreParserExpression YieldExpression;
     typedef PreParserExpression FunctionLiteral;
     typedef PreParserExpression ClassLiteral;
@@ skipping 72 matching lines @@
     UNREACHABLE();
   }
 
   static void CheckFunctionLiteralInsideTopLevelObjectLiteral(
       PreParserScope* scope, PreParserExpression property, bool* has_function) {
   }
 
   static void CheckAssigningFunctionLiteralToProperty(
       PreParserExpression left, PreParserExpression right) {}
 
-  // PreParser doesn't need to keep track of eval calls.
-  static void CheckPossibleEvalCall(PreParserExpression expression,
-                                    PreParserScope* scope) {}
+  // Need to record direct calls to eval so every variable in the enclosing
+  // scope gets allocated
+  void CheckPossibleEvalCall(PreParserExpression expression,
+                             PreParserScope* scope);
 
   static PreParserExpression MarkExpressionAsAssigned(
       PreParserExpression expression) {
     // TODO(marja): To be able to produce the same errors, the preparser needs
     // to start tracking which expressions are variables and which are assigned.
     return expression;
   }
 
+  void RecordCurrentSymbolAsIdentifierExpression();
+
   bool ShortcutNumericLiteralBinaryExpression(PreParserExpression* x,
                                               PreParserExpression y,
                                               Token::Value op,
                                               int pos,
                                               PreParserFactory* factory) {
     return false;
   }
 
   PreParserExpression BuildUnaryExpression(PreParserExpression expression,
                                            Token::Value op, int pos,
                                            PreParserFactory* factory) {
     return PreParserExpression::Default();
   }
 
   PreParserExpression NewThrowReferenceError(const char* type, int pos) {
     return PreParserExpression::Default();
   }
   PreParserExpression NewThrowSyntaxError(
       const char* type, Handle<Object> arg, int pos) {
     return PreParserExpression::Default();
   }
   PreParserExpression NewThrowTypeError(
       const char* type, Handle<Object> arg, int pos) {
     return PreParserExpression::Default();
   }
-  PreParserScope NewScope(PreParserScope* outer_scope, ScopeType scope_type) {
-    return PreParserScope(outer_scope, scope_type);
-  }
+  inline PreParserScope NewScope(PreParserScope* outer_scope,
+                                 ScopeType scope_type);
 
   // Reporting errors.
   void ReportMessageAt(Scanner::Location location,
                        const char* message,
                        const char* arg = NULL,
                        bool is_reference_error = false);
   void ReportMessageAt(int start_pos,
                        int end_pos,
                        const char* message,
                        const char* arg = NULL,
@@ skipping 70 matching lines @@
 
   PreParserExpression ExpressionFromString(int pos,
                                            Scanner* scanner,
                                            PreParserFactory* factory = NULL);
 
   PreParserExpression GetIterator(PreParserExpression iterable,
                                   PreParserFactory* factory) {
     return PreParserExpression::Default();
   }
 
-  static PreParserExpressionList NewExpressionList(int size, void* zone) {
+  static PreParserExpressionList NewExpressionList(int size, Zone* zone) {
     return PreParserExpressionList();
   }
 
-  static PreParserStatementList NewStatementList(int size, void* zone) {
+  static PreParserStatementList NewStatementList(int size, Zone* zone) {
     return PreParserStatementList();
   }
 
-  static PreParserExpressionList NewPropertyList(int size, void* zone) {
+  static PreParserExpressionList NewPropertyList(int size, Zone* zone) {
     return PreParserExpressionList();
   }
 
   V8_INLINE void SkipLazyFunctionBody(PreParserIdentifier function_name,
                                       int* materialized_literal_count,
                                       int* expected_property_count, bool* ok) {
     UNREACHABLE();
   }
 
   V8_INLINE PreParserStatementList
@@ skipping 44 matching lines @@
  public:
   typedef PreParserIdentifier Identifier;
   typedef PreParserExpression Expression;
   typedef PreParserStatement Statement;
 
   enum PreParseResult {
     kPreParseStackOverflow,
     kPreParseSuccess
   };
 
-  PreParser(Scanner* scanner, ParserRecorder* log, uintptr_t stack_limit)
-      : ParserBase<PreParserTraits>(scanner, stack_limit, NULL, log, NULL,
-                                    this) {}
+  PreParser(Scanner* scanner, ParserRecorder* log,
+            AstValueFactory* ast_value_factory, Zone* zone,
+            uintptr_t stack_limit)
+      : ParserBase<PreParserTraits>(scanner, stack_limit, NULL, log, zone,
+                                    this),
+        ast_value_factory_(ast_value_factory),
+        log_identifiers_(false) {}
 
   // Pre-parse the program from the character stream; returns true on
   // success (even if parsing failed, the pre-parse data successfully
   // captured the syntax error), and false if a stack-overflow happened
   // during parsing.
   PreParseResult PreParseProgram() {
-    PreParserScope scope(scope_, GLOBAL_SCOPE);
+    PreParserScope scope = NewScope(scope_, GLOBAL_SCOPE);
     PreParserFactory factory(NULL);
     FunctionState top_scope(&function_state_, &scope_, &scope, &factory);
     bool ok = true;
     int start_position = scanner()->peek_location().beg_pos;
     ParseSourceElements(Token::EOS, &ok);
     if (stack_overflow()) return kPreParseStackOverflow;
     if (!ok) {
       ReportUnexpectedToken(scanner()->current_token());
     } else if (scope_->strict_mode() == STRICT) {
       CheckOctalLiteral(start_position, scanner()->location().end_pos, &ok);
     }
     return kPreParseSuccess;
   }
 
   // Parses a single function literal, from the opening parentheses before
   // parameters to the closing brace after the body.
   // Returns a FunctionEntry describing the body of the function in enough
   // detail that it can be lazily compiled.
   // The scanner is expected to have matched the "function" or "function*"
   // keyword and parameters, and have consumed the initial '{'.
   // At return, unless an error occurred, the scanner is positioned before the
   // the final '}'.
-  PreParseResult PreParseLazyFunction(StrictMode strict_mode,
-                                      bool is_generator,
+  PreParseResult PreParseLazyFunction(StrictMode strict_mode, bool is_generator,
+                                      bool log_identifiers,
                                       ParserRecorder* log);
 
  private:
   friend class PreParserTraits;
 
   // These types form an algebra over syntactic categories that is just
   // rich enough to let us recognize and propagate the constructs that
   // are either being counted in the preparser data, or is important
   // to throw the correct syntax error exceptions.
 
@@ skipping 55 matching lines @@
                              Variable* fvar, Token::Value fvar_init_op,
                              bool is_generator, bool* ok);
 
   Expression ParseFunctionLiteral(
       Identifier name, Scanner::Location function_name_location,
       bool name_is_strict_reserved, FunctionKind kind, int function_token_pos,
       FunctionLiteral::FunctionType function_type,
       FunctionLiteral::ArityRestriction arity_restriction, bool* ok);
   void ParseLazyFunctionLiteralBody(bool* ok);
 
+  PreParserScope NewScope(PreParserScope* outer_scope, ScopeType scope_type) {
+    return PreParserScope(outer_scope, scope_type, zone(), log_identifiers_);
+  }
+
   bool CheckInOrOf(bool accept_OF);
+
+  AstValueFactory* ast_value_factory_;
+  bool log_identifiers_;
 };
 
 
 PreParserStatementList PreParser::ParseEagerFunctionBody(
     PreParserIdentifier function_name, int pos, Variable* fvar,
     Token::Value fvar_init_op, bool is_generator, bool* ok) {
   ParsingModeScope parsing_mode(this, PARSE_EAGERLY);
 
   ParseSourceElements(Token::RBRACE, ok);
   if (!*ok) return PreParserStatementList();
 
   Expect(Token::RBRACE, ok);
   return PreParserStatementList();
 }
 
 
 PreParserStatementList PreParserTraits::ParseEagerFunctionBody(
     PreParserIdentifier function_name, int pos, Variable* fvar,
     Token::Value fvar_init_op, bool is_generator, bool* ok) {
   return pre_parser_->ParseEagerFunctionBody(function_name, pos, fvar,
                                              fvar_init_op, is_generator, ok);
 }
 
 
+PreParserScope PreParserTraits::NewScope(PreParserScope* outer_scope,
+                                         ScopeType scope_type) {
+  return pre_parser_->NewScope(outer_scope, scope_type);
+}
+
+
 template <class Traits>
 ParserBase<Traits>::FunctionState::FunctionState(
     FunctionState** function_state_stack,
     typename Traits::Type::Scope** scope_stack,
     typename Traits::Type::Scope* scope,
     typename Traits::Type::Factory* factory)
     : next_materialized_literal_index_(JSFunction::kLiteralsPrefixSize),
       next_handler_index_(0),
       expected_property_count_(0),
       is_generator_(false),
@@ skipping 201 matching lines @@
       Next();
       result = this->ExpressionFromLiteral(token, pos, scanner(), factory());
       break;
 
     case Token::IDENTIFIER:
     case Token::LET:
     case Token::YIELD:
     case Token::FUTURE_STRICT_RESERVED_WORD: {
       // Using eval or arguments in this context is OK even in strict mode.
       IdentifierT name = ParseIdentifier(kAllowEvalOrArguments, CHECK_OK);
+      this->RecordCurrentSymbolAsIdentifierExpression();
       result = this->ExpressionFromIdentifier(name, pos, scope_, factory());
       break;
     }
 
     case Token::STRING: {
       Consume(Token::STRING);
       result = this->ExpressionFromString(pos, scanner(), factory());
       break;
     }
 
@@ skipping 231 matching lines @@
         FunctionKind::kNormalFunction, RelocInfo::kNoPosition,
         FunctionLiteral::ANONYMOUS_EXPRESSION,
         is_get ? FunctionLiteral::GETTER_ARITY : FunctionLiteral::SETTER_ARITY,
         CHECK_OK_CUSTOM(EmptyObjectLiteralProperty));
     return factory()->NewObjectLiteralProperty(is_get, value, next_pos,
                                                is_static);
 
   } else if (!in_class && allow_harmony_object_literals_ &&
              Token::IsIdentifier(name_token, strict_mode(),
                                  this->is_generator())) {
+    this->RecordCurrentSymbolAsIdentifierExpression();
     value = this->ExpressionFromIdentifier(name, next_pos, scope_, factory());
 
   } else {
     Token::Value next = Next();
     ReportUnexpectedToken(next);
     *ok = false;
     return this->EmptyObjectLiteralProperty();
   }
 
   uint32_t index;
@@ skipping 796 matching lines @@
       DCHECK(IsAccessorAccessorConflict(old_type, type));
       // Both accessors of the same type.
       parser()->ReportMessage("accessor_get_set");
     }
     *ok = false;
   }
 }
 } }  // v8::internal
 
 #endif  // V8_PREPARSER_H