text: // Copyright 2011 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
  //       with the distribution.
  //     * Neither the name of Google Inc. nor the names of its
  //       contributors may be used to endorse or promote products derived
  //       from this software without specific prior written permission.
  //
  // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  
  #include "v8.h"
  
  #include "ast.h"
  #include "parser.h"
  #include "scopes.h"
  #include "string-stream.h"
  #include "type-info.h"
  
  namespace v8 {
  namespace internal {
  
  AstSentinels::AstSentinels()
      : this_proxy_(Isolate::Current(), true),
        identifier_proxy_(Isolate::Current(), false),
        valid_left_hand_side_sentinel_(Isolate::Current()),
        this_property_(Isolate::Current(), &this_proxy_, NULL, 0),
        call_sentinel_(Isolate::Current(), NULL, NULL, 0) {
  }
  
  
  // ----------------------------------------------------------------------------
  // All the Accept member functions for each syntax tree node type.
  
  void Slot::Accept(AstVisitor* v) { v->VisitSlot(this); }
  
  #define DECL_ACCEPT(type)                                       \
    void type::Accept(AstVisitor* v) { v->Visit##type(this); }
  AST_NODE_LIST(DECL_ACCEPT)
  #undef DECL_ACCEPT
  
  
  // ----------------------------------------------------------------------------
  // Implementation of other node functionality.
  
  Assignment* ExpressionStatement::StatementAsSimpleAssignment() {
    return (expression()->AsAssignment() != NULL &&
            !expression()->AsAssignment()->is_compound())
        ? expression()->AsAssignment()
        : NULL;
  }
  
  
  CountOperation* ExpressionStatement::StatementAsCountOperation() {
    return expression()->AsCountOperation();
  }
  
  
  VariableProxy::VariableProxy(Isolate* isolate, Variable* var)
      : Expression(isolate),
        name_(var->name()),
        var_(NULL),  // Will be set by the call to BindTo.
        is_this_(var->is_this()),
        inside_with_(false),
        is_trivial_(false),
        position_(RelocInfo::kNoPosition) {
    BindTo(var);
  }
  
  
  VariableProxy::VariableProxy(Isolate* isolate,
                               Handle<String> name,
                               bool is_this,
                               bool inside_with,
                               int position)
      : Expression(isolate),
        name_(name),
        var_(NULL),
        is_this_(is_this),
        inside_with_(inside_with),
        is_trivial_(false),
        position_(position) {
    // Names must be canonicalized for fast equality checks.
    ASSERT(name->IsSymbol());
  }
  
  
  VariableProxy::VariableProxy(Isolate* isolate, bool is_this)
      : Expression(isolate),
        var_(NULL),
        is_this_(is_this),
        inside_with_(false),
        is_trivial_(false) {
  }
  
  
  void VariableProxy::BindTo(Variable* var) {
    ASSERT(var_ == NULL);  // must be bound only once
    ASSERT(var != NULL);  // must bind
    ASSERT((is_this() && var->is_this()) || name_.is_identical_to(var->name()));
    // Ideally CONST-ness should match. However, this is very hard to achieve
    // because we don't know the exact semantics of conflicting (const and
    // non-const) multiple variable declarations, const vars introduced via
    // eval() etc.  Const-ness and variable declarations are a complete mess
    // in JS. Sigh...
    var_ = var;
    var->set_is_used(true);
  }
  
  
  Assignment::Assignment(Isolate* isolate,
                         Token::Value op,
                         Expression* target,
                         Expression* value,
                         int pos)
      : Expression(isolate),
        op_(op),
        target_(target),
        value_(value),
        pos_(pos),
        binary_operation_(NULL),
        compound_load_id_(kNoNumber),
        assignment_id_(GetNextId(isolate)),
        block_start_(false),
        block_end_(false),
        is_monomorphic_(false),
        receiver_types_(NULL) {
    ASSERT(Token::IsAssignmentOp(op));
    if (is_compound()) {
      binary_operation_ =
          new(isolate->zone()) BinaryOperation(isolate,
                                               binary_op(),
                                               target,
                                               value,
                                               pos + 1);
      compound_load_id_ = GetNextId(isolate);
    }
  }
  
  
  Token::Value Assignment::binary_op() const {
    switch (op_) {
      case Token::ASSIGN_BIT_OR: return Token::BIT_OR;
      case Token::ASSIGN_BIT_XOR: return Token::BIT_XOR;
      case Token::ASSIGN_BIT_AND: return Token::BIT_AND;
      case Token::ASSIGN_SHL: return Token::SHL;
      case Token::ASSIGN_SAR: return Token::SAR;
      case Token::ASSIGN_SHR: return Token::SHR;
      case Token::ASSIGN_ADD: return Token::ADD;
      case Token::ASSIGN_SUB: return Token::SUB;
      case Token::ASSIGN_MUL: return Token::MUL;
      case Token::ASSIGN_DIV: return Token::DIV;
      case Token::ASSIGN_MOD: return Token::MOD;
      default: UNREACHABLE();
    }
    return Token::ILLEGAL;
  }
  
  
  bool FunctionLiteral::AllowsLazyCompilation() {
    return scope()->AllowsLazyCompilation();
  }
  
  
  ObjectLiteral::Property::Property(Literal* key, Expression* value) {
    emit_store_ = true;
    key_ = key;
    value_ = value;
    Object* k = *key->handle();
    if (k->IsSymbol() && HEAP->Proto_symbol()->Equals(String::cast(k))) {
      kind_ = PROTOTYPE;
    } else if (value_->AsMaterializedLiteral() != NULL) {
      kind_ = MATERIALIZED_LITERAL;
    } else if (value_->AsLiteral() != NULL) {
      kind_ = CONSTANT;
    } else {
      kind_ = COMPUTED;
    }
  }
  
  
  ObjectLiteral::Property::Property(bool is_getter, FunctionLiteral* value) {
    Isolate* isolate = Isolate::Current();
    emit_store_ = true;
    key_ = new(isolate->zone()) Literal(isolate, value->name());
    value_ = value;
    kind_ = is_getter ? GETTER : SETTER;
  }
  
  
  bool ObjectLiteral::Property::IsCompileTimeValue() {
    return kind_ == CONSTANT ||
        (kind_ == MATERIALIZED_LITERAL &&
         CompileTimeValue::IsCompileTimeValue(value_));
  }
  
  
  void ObjectLiteral::Property::set_emit_store(bool emit_store) {
    emit_store_ = emit_store;
  }
  
  
  bool ObjectLiteral::Property::emit_store() {
    return emit_store_;
  }
  
  
  bool IsEqualString(void* first, void* second) {
    ASSERT((*reinterpret_cast<String**>(first))->IsString());
    ASSERT((*reinterpret_cast<String**>(second))->IsString());
    Handle<String> h1(reinterpret_cast<String**>(first));
    Handle<String> h2(reinterpret_cast<String**>(second));
    return (*h1)->Equals(*h2);
  }
  
  
  bool IsEqualNumber(void* first, void* second) {
    ASSERT((*reinterpret_cast<Object**>(first))->IsNumber());
    ASSERT((*reinterpret_cast<Object**>(second))->IsNumber());
  
    Handle<Object> h1(reinterpret_cast<Object**>(first));
    Handle<Object> h2(reinterpret_cast<Object**>(second));
    if (h1->IsSmi()) {
      return h2->IsSmi() && *h1 == *h2;
    }
    if (h2->IsSmi()) return false;
    Handle<HeapNumber> n1 = Handle<HeapNumber>::cast(h1);
    Handle<HeapNumber> n2 = Handle<HeapNumber>::cast(h2);
    ASSERT(isfinite(n1->value()));
    ASSERT(isfinite(n2->value()));
    return n1->value() == n2->value();
  }
  
  
  void ObjectLiteral::CalculateEmitStore() {
    HashMap properties(&IsEqualString);
    HashMap elements(&IsEqualNumber);
    for (int i = this->properties()->length() - 1; i >= 0; i--) {
      ObjectLiteral::Property* property = this->properties()->at(i);
      Literal* literal = property->key();
      Handle<Object> handle = literal->handle();
  
      if (handle->IsNull()) {
        continue;
      }
  
      uint32_t hash;
      HashMap* table;
      void* key;
      Factory* factory = Isolate::Current()->factory();
      if (handle->IsSymbol()) {
        Handle<String> name(String::cast(*handle));
        if (name->AsArrayIndex(&hash)) {
          Handle<Object> key_handle = factory->NewNumberFromUint(hash);
          key = key_handle.location();
          table = &elements;
        } else {
          key = name.location();
          hash = name->Hash();
          table = &properties;
        }
      } else if (handle->ToArrayIndex(&hash)) {
        key = handle.location();
        table = &elements;
      } else {
        ASSERT(handle->IsNumber());
        double num = handle->Number();
        char arr[100];
        Vector<char> buffer(arr, ARRAY_SIZE(arr));
        const char* str = DoubleToCString(num, buffer);
        Handle<String> name = factory->NewStringFromAscii(CStrVector(str));
        key = name.location();
        hash = name->Hash();
        table = &properties;
      }
      // If the key of a computed property is in the table, do not emit
      // a store for the property later.
      if (property->kind() == ObjectLiteral::Property::COMPUTED) {
        if (table->Lookup(key, hash, false) != NULL) {
          property->set_emit_store(false);
        }
      }
      // Add key to the table.
      table->Lookup(key, hash, true);
    }
  }
  
  
  void TargetCollector::AddTarget(Label* target) {
    // Add the label to the collector, but discard duplicates.
    int length = targets_.length();
    for (int i = 0; i < length; i++) {
      if (targets_[i] == target) return;
    }
    targets_.Add(target);
  }
  
  
  bool UnaryOperation::ResultOverwriteAllowed() {
    switch (op_) {
      case Token::BIT_NOT:
      case Token::SUB:
        return true;
      default:
        return false;
    }
  }
  
  
  bool BinaryOperation::ResultOverwriteAllowed() {
    switch (op_) {
      case Token::COMMA:
      case Token::OR:
      case Token::AND:
        return false;
      case Token::BIT_OR:
      case Token::BIT_XOR:
      case Token::BIT_AND:
      case Token::SHL:
      case Token::SAR:
      case Token::SHR:
      case Token::ADD:
      case Token::SUB:
      case Token::MUL:
      case Token::DIV:
      case Token::MOD:
        return true;
      default:
        UNREACHABLE();
    }
    return false;
  }
  
  
  bool CompareOperation::IsLiteralCompareTypeof(Expression** expr,
                                                Handle<String>* check) {
    if (op_ != Token::EQ && op_ != Token::EQ_STRICT) return false;
  
    UnaryOperation* left_unary = left_->AsUnaryOperation();
    UnaryOperation* right_unary = right_->AsUnaryOperation();
    Literal* left_literal = left_->AsLiteral();
    Literal* right_literal = right_->AsLiteral();
  
    // Check for the pattern: typeof <expression> == <string literal>.
    if (left_unary != NULL && left_unary->op() == Token::TYPEOF &&
        right_literal != NULL && right_literal->handle()->IsString()) {
      *expr = left_unary->expression();
      *check = Handle<String>::cast(right_literal->handle());
      return true;
    }
  
    // Check for the pattern: <string literal> == typeof <expression>.
    if (right_unary != NULL && right_unary->op() == Token::TYPEOF &&
        left_literal != NULL && left_literal->handle()->IsString()) {
      *expr = right_unary->expression();
      *check = Handle<String>::cast(left_literal->handle());
      return true;
    }
  
    return false;
  }
  
  
  bool CompareOperation::IsLiteralCompareUndefined(Expression** expr) {
    if (op_ != Token::EQ_STRICT) return false;
  
    UnaryOperation* left_unary = left_->AsUnaryOperation();
    UnaryOperation* right_unary = right_->AsUnaryOperation();
  
    // Check for the pattern: <expression> === void <literal>.
    if (right_unary != NULL && right_unary->op() == Token::VOID &&
        right_unary->expression()->AsLiteral() != NULL) {
      *expr = left_;
      return true;
    }
  
    // Check for the pattern: void <literal> === <expression>.
    if (left_unary != NULL && left_unary->op() == Token::VOID &&
        left_unary->expression()->AsLiteral() != NULL) {
      *expr = right_;
      return true;
    }
  
    return false;
  }
  
  
  // ----------------------------------------------------------------------------
  // Inlining support
  
  bool Declaration::IsInlineable() const {
    return proxy()->var()->IsStackAllocated() && fun() == NULL;
  }
  
  
  bool TargetCollector::IsInlineable() const {
    UNREACHABLE();
    return false;
  }
  
  
  bool Slot::IsInlineable() const {
    UNREACHABLE();
    return false;
  }
  
  
  bool ForInStatement::IsInlineable() const {
    return false;
  }
  
  
  bool EnterWithContextStatement::IsInlineable() const {
    return false;
  }
  
  
  bool ExitContextStatement::IsInlineable() const {
    return false;
  }
  
  
  bool SwitchStatement::IsInlineable() const {
    return false;
  }
  
  
  bool TryStatement::IsInlineable() const {
    return false;
  }
  
  
  bool TryCatchStatement::IsInlineable() const {
    return false;
  }
  
  
  bool TryFinallyStatement::IsInlineable() const {
    return false;
  }
  
  
  bool DebuggerStatement::IsInlineable() const {
    return false;
  }
  
  
  bool Throw::IsInlineable() const {
    return exception()->IsInlineable();
  }
  
  
  bool MaterializedLiteral::IsInlineable() const {
    // TODO(1322): Allow materialized literals.
    return false;
  }
  
  
  bool FunctionLiteral::IsInlineable() const {
    // TODO(1322): Allow materialized literals.
    return false;
  }
  
  
  bool ThisFunction::IsInlineable() const {
    return false;
  }
  
  
  bool SharedFunctionInfoLiteral::IsInlineable() const {
    return false;
  }
  
  
  bool ValidLeftHandSideSentinel::IsInlineable() const {
    UNREACHABLE();
    return false;
  }
  
  
  bool ForStatement::IsInlineable() const {
    return (init() == NULL || init()->IsInlineable())
        && (cond() == NULL || cond()->IsInlineable())
        && (next() == NULL || next()->IsInlineable())
        && body()->IsInlineable();
  }
  
  
  bool WhileStatement::IsInlineable() const {
    return cond()->IsInlineable()
        && body()->IsInlineable();
  }
  
  
  bool DoWhileStatement::IsInlineable() const {
    return cond()->IsInlineable()
        && body()->IsInlineable();
  }
  
  
  bool ContinueStatement::IsInlineable() const {
    return true;
  }
  
  
  bool BreakStatement::IsInlineable() const {
    return true;
  }
  
  
  bool EmptyStatement::IsInlineable() const {
    return true;
  }
  
  
  bool Literal::IsInlineable() const {
    return true;
  }
  
  
  bool Block::IsInlineable() const {
    const int count = statements_.length();
    for (int i = 0; i < count; ++i) {
      if (!statements_[i]->IsInlineable()) return false;
    }
    return true;
  }
  
  
  bool ExpressionStatement::IsInlineable() const {
    return expression()->IsInlineable();
  }
  
  
  bool IfStatement::IsInlineable() const {
    return condition()->IsInlineable()
        && then_statement()->IsInlineable()
        && else_statement()->IsInlineable();
  }
  
  
  bool ReturnStatement::IsInlineable() const {
    return expression()->IsInlineable();
  }
  
  
  bool Conditional::IsInlineable() const {
    return condition()->IsInlineable() && then_expression()->IsInlineable() &&
        else_expression()->IsInlineable();
  }
  
  
  bool VariableProxy::IsInlineable() const {
    return var()->is_global() || var()->IsStackAllocated();
  }
  
  
  bool Assignment::IsInlineable() const {
    return target()->IsInlineable() && value()->IsInlineable();
  }
  
  
  bool Property::IsInlineable() const {
    return obj()->IsInlineable() && key()->IsInlineable();
  }
  
  
  bool Call::IsInlineable() const {
    if (!expression()->IsInlineable()) return false;
    const int count = arguments()->length();
    for (int i = 0; i < count; ++i) {
      if (!arguments()->at(i)->IsInlineable()) return false;
    }
    return true;
  }
  
  
  bool CallNew::IsInlineable() const {
    if (!expression()->IsInlineable()) return false;
    const int count = arguments()->length();
    for (int i = 0; i < count; ++i) {
      if (!arguments()->at(i)->IsInlineable()) return false;
    }
    return true;
  }
  
  
  bool CallRuntime::IsInlineable() const {
    // Don't try to inline JS runtime calls because we don't (currently) even
    // optimize them.
    if (is_jsruntime()) return false;
    // Don't inline the %_ArgumentsLength or %_Arguments because their
    // implementation will not work.  There is no stack frame to get them
    // from.
    if (function()->intrinsic_type == Runtime::INLINE &&
        (name()->IsEqualTo(CStrVector("_ArgumentsLength")) ||
         name()->IsEqualTo(CStrVector("_Arguments")))) {
      return false;
    }
    const int count = arguments()->length();
    for (int i = 0; i < count; ++i) {
      if (!arguments()->at(i)->IsInlineable()) return false;
    }
    return true;
  }
  
  
  bool UnaryOperation::IsInlineable() const {
    return expression()->IsInlineable();
  }
  
  
  bool BinaryOperation::IsInlineable() const {
    return left()->IsInlineable() && right()->IsInlineable();
  }
  
  
  bool CompareOperation::IsInlineable() const {
    return left()->IsInlineable() && right()->IsInlineable();
  }
  
  
  bool CompareToNull::IsInlineable() const {
    return expression()->IsInlineable();
  }
  
  
  bool CountOperation::IsInlineable() const {
    return expression()->IsInlineable();
  }
  
  
  // ----------------------------------------------------------------------------
  // Recording of type feedback
  
  void Property::RecordTypeFeedback(TypeFeedbackOracle* oracle) {
    // Record type feedback from the oracle in the AST.
    is_monomorphic_ = oracle->LoadIsMonomorphicNormal(this);
    if (key()->IsPropertyName()) {
      if (oracle->LoadIsBuiltin(this, Builtins::kLoadIC_ArrayLength)) {
        is_array_length_ = true;
      } else if (oracle->LoadIsBuiltin(this, Builtins::kLoadIC_StringLength)) {
        is_string_length_ = true;
      } else if (oracle->LoadIsBuiltin(this,
                                       Builtins::kLoadIC_FunctionPrototype)) {
        is_function_prototype_ = true;
      } else {
        Literal* lit_key = key()->AsLiteral();
        ASSERT(lit_key != NULL && lit_key->handle()->IsString());
        Handle<String> name = Handle<String>::cast(lit_key->handle());
        ZoneMapList* types = oracle->LoadReceiverTypes(this, name);
        receiver_types_ = types;
      }
    } else if (oracle->LoadIsBuiltin(this, Builtins::kKeyedLoadIC_String)) {
      is_string_access_ = true;
    } else if (is_monomorphic_) {
      monomorphic_receiver_type_ = oracle->LoadMonomorphicReceiverType(this);
    } else if (oracle->LoadIsMegamorphicWithTypeInfo(this)) {
      receiver_types_ = new ZoneMapList(kMaxKeyedPolymorphism);
      oracle->CollectKeyedReceiverTypes(this->id(), receiver_types_);
    }
  }
  
  
  void Assignment::RecordTypeFeedback(TypeFeedbackOracle* oracle) {
    Property* prop = target()->AsProperty();
    ASSERT(prop != NULL);
    is_monomorphic_ = oracle->StoreIsMonomorphicNormal(this);
    if (prop->key()->IsPropertyName()) {
      Literal* lit_key = prop->key()->AsLiteral();
      ASSERT(lit_key != NULL && lit_key->handle()->IsString());
      Handle<String> name = Handle<String>::cast(lit_key->handle());
      ZoneMapList* types = oracle->StoreReceiverTypes(this, name);
      receiver_types_ = types;
    } else if (is_monomorphic_) {
      // Record receiver type for monomorphic keyed stores.
      monomorphic_receiver_type_ = oracle->StoreMonomorphicReceiverType(this);
    } else if (oracle->StoreIsMegamorphicWithTypeInfo(this)) {
      receiver_types_ = new ZoneMapList(kMaxKeyedPolymorphism);
      oracle->CollectKeyedReceiverTypes(this->id(), receiver_types_);
    }
  }
  
  
  void CountOperation::RecordTypeFeedback(TypeFeedbackOracle* oracle) {
    is_monomorphic_ = oracle->StoreIsMonomorphicNormal(this);
    if (is_monomorphic_) {
      // Record receiver type for monomorphic keyed stores.
      monomorphic_receiver_type_ = oracle->StoreMonomorphicReceiverType(this);
    } else if (oracle->StoreIsMegamorphicWithTypeInfo(this)) {
      receiver_types_ = new ZoneMapList(kMaxKeyedPolymorphism);
      oracle->CollectKeyedReceiverTypes(this->id(), receiver_types_);
    }
  }
  
  
  void CaseClause::RecordTypeFeedback(TypeFeedbackOracle* oracle) {
    TypeInfo info = oracle->SwitchType(this);
    if (info.IsSmi()) {
      compare_type_ = SMI_ONLY;
    } else if (info.IsNonPrimitive()) {
      compare_type_ = OBJECT_ONLY;
    } else {
      ASSERT(compare_type_ == NONE);
    }
  }
  
  
  static bool CanCallWithoutIC(Handle<JSFunction> target, int arity) {
    SharedFunctionInfo* info = target->shared();
    // If the number of formal parameters of the target function does
    // not match the number of arguments we're passing, we don't want to
    // deal with it. Otherwise, we can call it directly.
    return !target->NeedsArgumentsAdaption() ||
        info->formal_parameter_count() == arity;
  }
  
  
  bool Call::ComputeTarget(Handle<Map> type, Handle<String> name) {
    if (check_type_ == RECEIVER_MAP_CHECK) {
      // For primitive checks the holder is set up to point to the
      // corresponding prototype object, i.e. one step of the algorithm
      // below has been already performed.
      // For non-primitive checks we clear it to allow computing targets
      // for polymorphic calls.
      holder_ = Handle<JSObject>::null();
    }
    while (true) {
      LookupResult lookup;
      type->LookupInDescriptors(NULL, *name, &lookup);
      // If the function wasn't found directly in the map, we start
      // looking upwards through the prototype chain.
      if (!lookup.IsFound() && type->prototype()->IsJSObject()) {
        holder_ = Handle<JSObject>(JSObject::cast(type->prototype()));
        type = Handle<Map>(holder()->map());
      } else if (lookup.IsProperty() && lookup.type() == CONSTANT_FUNCTION) {
        target_ = Handle<JSFunction>(lookup.GetConstantFunctionFromMap(*type));
        return CanCallWithoutIC(target_, arguments()->length());
      } else {
        return false;
      }
    }
  }
  
  
  bool Call::ComputeGlobalTarget(Handle<GlobalObject> global,
                                 LookupResult* lookup) {
    target_ = Handle<JSFunction>::null();
    cell_ = Handle<JSGlobalPropertyCell>::null();
    ASSERT(lookup->IsProperty() &&
           lookup->type() == NORMAL &&
           lookup->holder() == *global);
    cell_ = Handle<JSGlobalPropertyCell>(global->GetPropertyCell(lookup));
    if (cell_->value()->IsJSFunction()) {
      Handle<JSFunction> candidate(JSFunction::cast(cell_->value()));
      // If the function is in new space we assume it's more likely to
      // change and thus prefer the general IC code.
      if (!HEAP->InNewSpace(*candidate) &&
          CanCallWithoutIC(candidate, arguments()->length())) {
        target_ = candidate;
        return true;
      }
    }
    return false;
  }
  
  
  void Call::RecordTypeFeedback(TypeFeedbackOracle* oracle,
                                CallKind call_kind) {
    Property* property = expression()->AsProperty();
    ASSERT(property != NULL);
    // Specialize for the receiver types seen at runtime.
    Literal* key = property->key()->AsLiteral();
    ASSERT(key != NULL && key->handle()->IsString());
    Handle<String> name = Handle<String>::cast(key->handle());
    receiver_types_ = oracle->CallReceiverTypes(this, name, call_kind);
  #ifdef DEBUG
    if (FLAG_enable_slow_asserts) {
      if (receiver_types_ != NULL) {
        int length = receiver_types_->length();
        for (int i = 0; i < length; i++) {
          Handle<Map> map = receiver_types_->at(i);
          ASSERT(!map.is_null() && *map != NULL);
        }
      }
    }
  #endif
    is_monomorphic_ = oracle->CallIsMonomorphic(this);
    check_type_ = oracle->GetCallCheckType(this);
    if (is_monomorphic_) {
      Handle<Map> map;
      if (receiver_types_ != NULL && receiver_types_->length() > 0) {
        ASSERT(check_type_ == RECEIVER_MAP_CHECK);
        map = receiver_types_->at(0);
      } else {
        ASSERT(check_type_ != RECEIVER_MAP_CHECK);
        holder_ = Handle<JSObject>(
            oracle->GetPrototypeForPrimitiveCheck(check_type_));
        map = Handle<Map>(holder_->map());
      }
      is_monomorphic_ = ComputeTarget(map, name);
    }
  }
  
  
  void CompareOperation::RecordTypeFeedback(TypeFeedbackOracle* oracle) {
    TypeInfo info = oracle->CompareType(this);
    if (info.IsSmi()) {
      compare_type_ = SMI_ONLY;
    } else if (info.IsNonPrimitive()) {
      compare_type_ = OBJECT_ONLY;
    } else {
      ASSERT(compare_type_ == NONE);
    }
  }
  
  
  // ----------------------------------------------------------------------------
  // Implementation of AstVisitor
  
  bool AstVisitor::CheckStackOverflow() {
    if (stack_overflow_) return true;
    StackLimitCheck check(isolate_);
    if (!check.HasOverflowed()) return false;
    return (stack_overflow_ = true);
  }
  
  
  void AstVisitor::VisitDeclarations(ZoneList<Declaration*>* declarations) {
    for (int i = 0; i < declarations->length(); i++) {
      Visit(declarations->at(i));
    }
  }
  
  
  void AstVisitor::VisitStatements(ZoneList<Statement*>* statements) {
    for (int i = 0; i < statements->length(); i++) {
      Visit(statements->at(i));
    }
  }
  
  
  void AstVisitor::VisitExpressions(ZoneList<Expression*>* expressions) {
    for (int i = 0; i < expressions->length(); i++) {
      // The variable statement visiting code may pass NULL expressions
      // to this code. Maybe this should be handled by introducing an
      // undefined expression or literal?  Revisit this code if this
      // changes
      Expression* expression = expressions->at(i);
      if (expression != NULL) Visit(expression);
    }
  }
  
  
  // ----------------------------------------------------------------------------
  // Regular expressions
  
  #define MAKE_ACCEPT(Name)                                            \
    void* RegExp##Name::Accept(RegExpVisitor* visitor, void* data) {   \
      return visitor->Visit##Name(this, data);                         \
    }
  FOR_EACH_REG_EXP_TREE_TYPE(MAKE_ACCEPT)
  #undef MAKE_ACCEPT
  
  #define MAKE_TYPE_CASE(Name)                                         \
    RegExp##Name* RegExpTree::As##Name() {                             \
      return NULL;                                                     \
    }                                                                  \
    bool RegExpTree::Is##Name() { return false; }
  FOR_EACH_REG_EXP_TREE_TYPE(MAKE_TYPE_CASE)
  #undef MAKE_TYPE_CASE
  
  #define MAKE_TYPE_CASE(Name)                                        \
    RegExp##Name* RegExp##Name::As##Name() {                          \
      return this;                                                    \
    }                                                                 \
    bool RegExp##Name::Is##Name() { return true; }
  FOR_EACH_REG_EXP_TREE_TYPE(MAKE_TYPE_CASE)
  #undef MAKE_TYPE_CASE
  
  RegExpEmpty RegExpEmpty::kInstance;
  
  
  static Interval ListCaptureRegisters(ZoneList<RegExpTree*>* children) {
    Interval result = Interval::Empty();
    for (int i = 0; i < children->length(); i++)
      result = result.Union(children->at(i)->CaptureRegisters());
    return result;
  }
  
  
  Interval RegExpAlternative::CaptureRegisters() {
    return ListCaptureRegisters(nodes());
  }
  
  
  Interval RegExpDisjunction::CaptureRegisters() {
    return ListCaptureRegisters(alternatives());
  }
  
  
  Interval RegExpLookahead::CaptureRegisters() {
    return body()->CaptureRegisters();
  }
  
  
  Interval RegExpCapture::CaptureRegisters() {
    Interval self(StartRegister(index()), EndRegister(index()));
    return self.Union(body()->CaptureRegisters());
  }
  
  
  Interval RegExpQuantifier::CaptureRegisters() {
    return body()->CaptureRegisters();
  }
  
  
  bool RegExpAssertion::IsAnchoredAtStart() {
    return type() == RegExpAssertion::START_OF_INPUT;
  }
  
  
  bool RegExpAssertion::IsAnchoredAtEnd() {
    return type() == RegExpAssertion::END_OF_INPUT;
  }
  
  
  bool RegExpAlternative::IsAnchoredAtStart() {
    ZoneList<RegExpTree*>* nodes = this->nodes();
    for (int i = 0; i < nodes->length(); i++) {
      RegExpTree* node = nodes->at(i);
      if (node->IsAnchoredAtStart()) { return true; }
      if (node->max_match() > 0) { return false; }
    }
    return false;
  }
  
  
  bool RegExpAlternative::IsAnchoredAtEnd() {
    ZoneList<RegExpTree*>* nodes = this->nodes();
    for (int i = nodes->length() - 1; i >= 0; i--) {
      RegExpTree* node = nodes->at(i);
      if (node->IsAnchoredAtEnd()) { return true; }
      if (node->max_match() > 0) { return false; }
    }
    return false;
  }
  
  
  bool RegExpDisjunction::IsAnchoredAtStart() {
    ZoneList<RegExpTree*>* alternatives = this->alternatives();
    for (int i = 0; i < alternatives->length(); i++) {
      if (!alternatives->at(i)->IsAnchoredAtStart())
        return false;
    }
    return true;
  }
  
  
  bool RegExpDisjunction::IsAnchoredAtEnd() {
    ZoneList<RegExpTree*>* alternatives = this->alternatives();
    for (int i = 0; i < alternatives->length(); i++) {
      if (!alternatives->at(i)->IsAnchoredAtEnd())
        return false;
    }
    return true;
  }
  
  
  bool RegExpLookahead::IsAnchoredAtStart() {
    return is_positive() && body()->IsAnchoredAtStart();
  }
  
  
  bool RegExpCapture::IsAnchoredAtStart() {
    return body()->IsAnchoredAtStart();
  }
  
  
  bool RegExpCapture::IsAnchoredAtEnd() {
    return body()->IsAnchoredAtEnd();
  }
  
  
  // Convert regular expression trees to a simple sexp representation.
  // This representation should be different from the input grammar
  // in as many cases as possible, to make it more difficult for incorrect
  // parses to look as correct ones which is likely if the input and
  // output formats are alike.
  class RegExpUnparser: public RegExpVisitor {
   public:
    RegExpUnparser();
    void VisitCharacterRange(CharacterRange that);
    SmartPointer<const char> ToString() { return stream_.ToCString(); }
  #define MAKE_CASE(Name) virtual void* Visit##Name(RegExp##Name*, void* data);
    FOR_EACH_REG_EXP_TREE_TYPE(MAKE_CASE)
  #undef MAKE_CASE
   private:
    StringStream* stream() { return &stream_; }
    HeapStringAllocator alloc_;
    StringStream stream_;
  };
  
  
  RegExpUnparser::RegExpUnparser() : stream_(&alloc_) {
  }
  
  
  void* RegExpUnparser::VisitDisjunction(RegExpDisjunction* that, void* data) {
    stream()->Add("(|");
    for (int i = 0; i <  that->alternatives()->length(); i++) {
      stream()->Add(" ");
      that->alternatives()->at(i)->Accept(this, data);
    }
    stream()->Add(")");
    return NULL;
  }
  
  
  void* RegExpUnparser::VisitAlternative(RegExpAlternative* that, void* data) {
    stream()->Add("(:");
    for (int i = 0; i <  that->nodes()->length(); i++) {
      stream()->Add(" ");
      that->nodes()->at(i)->Accept(this, data);
    }
    stream()->Add(")");
    return NULL;
  }
  
  
  void RegExpUnparser::VisitCharacterRange(CharacterRange that) {
    stream()->Add("%k", that.from());
    if (!that.IsSingleton()) {
      stream()->Add("-%k", that.to());
    }
  }
  
  
  
  void* RegExpUnparser::VisitCharacterClass(RegExpCharacterClass* that,
                                            void* data) {
    if (that->is_negated())
      stream()->Add("^");
    stream()->Add("[");
    for (int i = 0; i < that->ranges()->length(); i++) {
      if (i > 0) stream()->Add(" ");
      VisitCharacterRange(that->ranges()->at(i));
    }
    stream()->Add("]");
    return NULL;
  }
  
  
  void* RegExpUnparser::VisitAssertion(RegExpAssertion* that, void* data) {
    switch (that->type()) {
      case RegExpAssertion::START_OF_INPUT:
        stream()->Add("@^i");
        break;
      case RegExpAssertion::END_OF_INPUT:
        stream()->Add("@$i");
        break;
      case RegExpAssertion::START_OF_LINE:
        stream()->Add("@^l");
        break;
      case RegExpAssertion::END_OF_LINE:
        stream()->Add("@$l");
         break;
      case RegExpAssertion::BOUNDARY:
        stream()->Add("@b");
        break;
      case RegExpAssertion::NON_BOUNDARY:
        stream()->Add("@B");
        break;
    }
    return NULL;
  }
  
  
  void* RegExpUnparser::VisitAtom(RegExpAtom* that, void* data) {
    stream()->Add("'");
    Vector<const uc16> chardata = that->data();
    for (int i = 0; i < chardata.length(); i++) {
      stream()->Add("%k", chardata[i]);
    }
    stream()->Add("'");
    return NULL;
  }
  
  
  void* RegExpUnparser::VisitText(RegExpText* that, void* data) {
    if (that->elements()->length() == 1) {
      that->elements()->at(0).data.u_atom->Accept(this, data);
    } else {
      stream()->Add("(!");
      for (int i = 0; i < that->elements()->length(); i++) {
        stream()->Add(" ");
        that->elements()->at(i).data.u_atom->Accept(this, data);
      }
      stream()->Add(")");
    }
    return NULL;
  }
  
  
  void* RegExpUnparser::VisitQuantifier(RegExpQuantifier* that, void* data) {
    stream()->Add("(# %i ", that->min());
    if (that->max() == RegExpTree::kInfinity) {
      stream()->Add("- ");
    } else {
      stream()->Add("%i ", that->max());
    }
    stream()->Add(that->is_greedy() ? "g " : that->is_possessive() ? "p " : "n ");
    that->body()->Accept(this, data);
    stream()->Add(")");
    return NULL;
  }
  
  
  void* RegExpUnparser::VisitCapture(RegExpCapture* that, void* data) {
    stream()->Add("(^ ");
    that->body()->Accept(this, data);
    stream()->Add(")");
    return NULL;
  }
  
  
  void* RegExpUnparser::VisitLookahead(RegExpLookahead* that, void* data) {
    stream()->Add("(-> ");
    stream()->Add(that->is_positive() ? "+ " : "- ");
    that->body()->Accept(this, data);
    stream()->Add(")");
    return NULL;
  }
  
  
  void* RegExpUnparser::VisitBackReference(RegExpBackReference* that,
                                           void* data) {
    stream()->Add("(<- %i)", that->index());
    return NULL;
  }
  
  
  void* RegExpUnparser::VisitEmpty(RegExpEmpty* that, void* data) {
    stream()->Put('%');
    return NULL;
  }
  
  
  SmartPointer<const char> RegExpTree::ToString() {
    RegExpUnparser unparser;
    Accept(&unparser, NULL);
    return unparser.ToString();
  }
  
  
  RegExpDisjunction::RegExpDisjunction(ZoneList<RegExpTree*>* alternatives)
      : alternatives_(alternatives) {
    ASSERT(alternatives->length() > 1);
    RegExpTree* first_alternative = alternatives->at(0);
    min_match_ = first_alternative->min_match();
    max_match_ = first_alternative->max_match();
    for (int i = 1; i < alternatives->length(); i++) {
      RegExpTree* alternative = alternatives->at(i);
      min_match_ = Min(min_match_, alternative->min_match());
      max_match_ = Max(max_match_, alternative->max_match());
    }
  }
  
  
  RegExpAlternative::RegExpAlternative(ZoneList<RegExpTree*>* nodes)
      : nodes_(nodes) {
    ASSERT(nodes->length() > 1);
    min_match_ = 0;
    max_match_ = 0;
    for (int i = 0; i < nodes->length(); i++) {
      RegExpTree* node = nodes->at(i);
      min_match_ += node->min_match();
      int node_max_match = node->max_match();
      if (kInfinity - max_match_ < node_max_match) {
        max_match_ = kInfinity;
      } else {
        max_match_ += node->max_match();
      }
    }
  }
  
  
  CaseClause::CaseClause(Isolate* isolate,
                         Expression* label,
                         ZoneList<Statement*>* statements,
                         int pos)
      : label_(label),
        statements_(statements),
        position_(pos),
        compare_type_(NONE),
        compare_id_(AstNode::GetNextId(isolate)),
        entry_id_(AstNode::GetNextId(isolate)) {
  }
  
  } }  // namespace v8::internal
  