[kernel] Streaming ScopeBuilder

runtime/vm/kernel_to_il.cc

Index: runtime/vm/kernel_to_il.cc
diff --git a/runtime/vm/kernel_to_il.cc b/runtime/vm/kernel_to_il.cc
index 7635053d71dcc957bb8896bc0b7c96266c7faa66..5b10f05fa41a64ffd304d0ef1c7eb76b1348fe06 100644
--- a/runtime/vm/kernel_to_il.cc
+++ b/runtime/vm/kernel_to_il.cc
@@ -57,225 +57,6 @@ static void DiscoverEnclosingElements(Zone* zone,
 }
 
 
-ScopeBuilder::ScopeBuilder(ParsedFunction* parsed_function, TreeNode* node)
-    : result_(NULL),
-      parsed_function_(parsed_function),
-      node_(node),
-      translation_helper_(Thread::Current()),
-      zone_(translation_helper_.zone()),
-      type_translator_(&translation_helper_, &active_class_, /*finalize=*/true),
-      current_function_scope_(NULL),
-      scope_(NULL),
-      depth_(0),
-      name_index_(0),
-      needs_expr_temp_(false) {
-  Script& script = Script::Handle(Z, parsed_function->function().script());
-  H.SetStringOffsets(TypedData::Handle(Z, script.kernel_string_offsets()));
-  H.SetStringData(TypedData::Handle(Z, script.kernel_string_data()));
-  H.SetCanonicalNames(TypedData::Handle(Z, script.kernel_canonical_names()));
-}
-
-
-void ScopeBuilder::EnterScope(TreeNode* node, TokenPosition start_position) {
-  scope_ = new (Z) LocalScope(scope_, depth_.function_, depth_.loop_);
-  scope_->set_begin_token_pos(start_position);
-  ASSERT(node->kernel_offset() >= 0);
-  result_->scopes.Insert(node->kernel_offset(), scope_);
-}
-
-
-void ScopeBuilder::ExitScope(TokenPosition end_position) {
-  scope_->set_end_token_pos(end_position);
-  scope_ = scope_->parent();
-}
-
-
-LocalVariable* ScopeBuilder::MakeVariable(TokenPosition declaration_pos,
-                                          TokenPosition token_pos,
-                                          const dart::String& name,
-                                          const AbstractType& type) {
-  return new (Z) LocalVariable(declaration_pos, token_pos, name, type);
-}
-
-
-void ScopeBuilder::AddParameters(FunctionNode* function, intptr_t pos) {
-  List<VariableDeclaration>& positional = function->positional_parameters();
-  for (intptr_t i = 0; i < positional.length(); ++i) {
-    AddParameter(positional[i], pos++);
-  }
-  List<VariableDeclaration>& named = function->named_parameters();
-  for (intptr_t i = 0; i < named.length(); ++i) {
-    AddParameter(named[i], pos++);
-  }
-}
-
-
-void ScopeBuilder::AddParameter(VariableDeclaration* declaration,
-                                intptr_t pos) {
-  LocalVariable* variable = MakeVariable(
-      declaration->position(), declaration->position(),
-      H.DartSymbol(declaration->name()), T.TranslateVariableType(declaration));
-  if (declaration->IsFinal()) {
-    variable->set_is_final();
-  }
-  if (variable->name().raw() == Symbols::IteratorParameter().raw()) {
-    variable->set_is_forced_stack();
-  }
-  scope_->InsertParameterAt(pos, variable);
-  result_->locals.Insert(declaration->kernel_offset(), variable);
-
-  // The default value may contain 'let' bindings for which the constant
-  // evaluator needs scope bindings.
-  Expression* defaultValue = declaration->initializer();
-  if (defaultValue != NULL) {
-    defaultValue->AcceptExpressionVisitor(this);
-  }
-}
-
-
-void ScopeBuilder::AddExceptionVariable(
-    GrowableArray<LocalVariable*>* variables,
-    const char* prefix,
-    intptr_t nesting_depth) {
-  LocalVariable* v = NULL;
-
-  // If we are inside a function with yield points then Kernel transformer
-  // could have lifted some of the auxiliary exception variables into the
-  // context to preserve them across yield points because they might
-  // be needed for rethrow.
-  // Check if it did and capture such variables instead of introducing
-  // new local ones.
-  // Note: function that wrap kSyncYielding function does not contain
-  // its own try/catches.
-  if (current_function_node_->async_marker() == FunctionNode::kSyncYielding) {
-    ASSERT(current_function_scope_->parent() != NULL);
-    v = current_function_scope_->parent()->LocalLookupVariable(
-        GenerateName(prefix, nesting_depth - 1));
-    if (v != NULL) {
-      scope_->CaptureVariable(v);
-    }
-  }
-
-  // No need to create variables for try/catch-statements inside
-  // nested functions.
-  if (depth_.function_ > 0) return;
-  if (variables->length() >= nesting_depth) return;
-
-  // If variable was not lifted by the transformer introduce a new
-  // one into the current function scope.
-  if (v == NULL) {
-    v = MakeVariable(TokenPosition::kNoSource, TokenPosition::kNoSource,
-                     GenerateName(prefix, nesting_depth - 1),
-                     AbstractType::dynamic_type());
-
-    // If transformer did not lift the variable then there is no need
-    // to lift it into the context when we encouter a YieldStatement.
-    v->set_is_forced_stack();
-    current_function_scope_->AddVariable(v);
-  }
-
-  variables->Add(v);
-}
-
-
-void ScopeBuilder::AddTryVariables() {
-  AddExceptionVariable(&result_->catch_context_variables,
-                       ":saved_try_context_var", depth_.try_);
-}
-
-
-void ScopeBuilder::AddCatchVariables() {
-  AddExceptionVariable(&result_->exception_variables, ":exception",
-                       depth_.catch_);
-  AddExceptionVariable(&result_->stack_trace_variables, ":stack_trace",
-                       depth_.catch_);
-}
-
-
-void ScopeBuilder::AddIteratorVariable() {
-  if (depth_.function_ > 0) return;
-  if (result_->iterator_variables.length() >= depth_.for_in_) return;
-
-  ASSERT(result_->iterator_variables.length() == depth_.for_in_ - 1);
-  LocalVariable* iterator =
-      MakeVariable(TokenPosition::kNoSource, TokenPosition::kNoSource,
-                   GenerateName(":iterator", depth_.for_in_ - 1),
-                   AbstractType::dynamic_type());
-  current_function_scope_->AddVariable(iterator);
-  result_->iterator_variables.Add(iterator);
-}
-
-
-void ScopeBuilder::LookupVariable(VariableDeclaration* declaration) {
-  LocalVariable* variable =
-      result_->locals.Lookup(declaration->kernel_offset());
-  if (variable == NULL) {
-    // We have not seen a declaration of the variable, so it must be the
-    // case that we are compiling a nested function and the variable is
-    // declared in an outer scope.  In that case, look it up in the scope by
-    // name and add it to the variable map to simplify later lookup.
-    ASSERT(current_function_scope_->parent() != NULL);
-    const dart::String& name = H.DartSymbol(declaration->name());
-    variable = current_function_scope_->parent()->LookupVariable(name, true);
-    ASSERT(variable != NULL);
-    result_->locals.Insert(declaration->kernel_offset(), variable);
-  }
-  if (variable->owner()->function_level() < scope_->function_level()) {
-    // We call `LocalScope->CaptureVariable(variable)` in two scenarios for two
-    // different reasons:
-    //   Scenario 1:
-    //       We need to know which variables defined in this function
-    //       are closed over by nested closures in order to ensure we will
-    //       create a [Context] object of appropriate size and store captured
-    //       variables there instead of the stack.
-    //   Scenario 2:
-    //       We need to find out which variables defined in enclosing functions
-    //       are closed over by this function/closure or nested closures. This
-    //       is necessary in order to build a fat flattened [ContextScope]
-    //       object.
-    scope_->CaptureVariable(variable);
-  } else {
-    ASSERT(variable->owner()->function_level() == scope_->function_level());
-  }
-}
-
-
-void ScopeBuilder::LookupCapturedVariableByName(LocalVariable** variable,
-                                                const dart::String& name) {
-  if (*variable == NULL) {
-    *variable = scope_->LookupVariable(name, true);
-    ASSERT(*variable != NULL);
-    scope_->CaptureVariable(*variable);
-  }
-}
-
-
-const dart::String& ScopeBuilder::GenerateName(const char* prefix,
-                                               intptr_t suffix) {
-  char name[64];
-  OS::SNPrint(name, 64, "%s%" Pd "", prefix, suffix);
-  return H.DartSymbol(name);
-}
-
-
-void ScopeBuilder::AddVariable(VariableDeclaration* declaration) {
-  // In case `declaration->IsConst()` the flow graph building will take care of
-  // evaluating the constant and setting it via
-  // `declaration->SetConstantValue()`.
-  const dart::String& name = (H.StringSize(declaration->name()) == 0)
-                                 ? GenerateName(":var", name_index_++)
-                                 : H.DartSymbol(declaration->name());
-  LocalVariable* variable =
-      MakeVariable(declaration->position(), declaration->end_position(), name,
-                   T.TranslateVariableType(declaration));
-  if (declaration->IsFinal()) {
-    variable->set_is_final();
-  }
-  scope_->AddVariable(variable);
-  result_->locals.Insert(declaration->kernel_offset(), variable);
-}
-
-
 static bool IsStaticInitializer(const Function& function, Zone* zone) {
   return (function.kind() == RawFunction::kImplicitStaticFinalGetter) &&
          dart::String::Handle(zone, function.name())
@@ -283,539 +64,6 @@ static bool IsStaticInitializer(const Function& function, Zone* zone) {
 }
 
 
-ScopeBuildingResult* ScopeBuilder::BuildScopes() {
-  if (result_ != NULL) return result_;
-
-  ASSERT(scope_ == NULL && depth_.loop_ == 0 && depth_.function_ == 0);
-  result_ = new (Z) ScopeBuildingResult();
-
-  ParsedFunction* parsed_function = parsed_function_;
-  const Function& function = parsed_function->function();
-
-  // Setup a [ActiveClassScope] and a [ActiveMemberScope] which will be used
-  // e.g. for type translation.
-  const dart::Class& klass =
-      dart::Class::Handle(zone_, parsed_function_->function().Owner());
-  Function& outermost_function = Function::Handle(Z);
-  TreeNode* outermost_node = NULL;
-  Class* kernel_class = NULL;
-  DiscoverEnclosingElements(Z, function, &outermost_function, &outermost_node,
-                            &kernel_class);
-  // Use [klass]/[kernel_class] as active class.  Type parameters will get
-  // resolved via [kernel_class] unless we are nested inside a static factory
-  // in which case we will use [member].
-  ActiveClassScope active_class_scope(&active_class_, kernel_class, &klass);
-  Member* member = ((outermost_node != NULL) && outermost_node->IsMember())
-                       ? Member::Cast(outermost_node)
-                       : NULL;
-  ActiveMemberScope active_member(&active_class_, member);
-
-
-  LocalScope* enclosing_scope = NULL;
-  if (function.IsLocalFunction()) {
-    enclosing_scope = LocalScope::RestoreOuterScope(
-        ContextScope::Handle(Z, function.context_scope()));
-  }
-  current_function_scope_ = scope_ = new (Z) LocalScope(enclosing_scope, 0, 0);
-  scope_->set_begin_token_pos(function.token_pos());
-  scope_->set_end_token_pos(function.end_token_pos());
-
-  LocalVariable* context_var = parsed_function->current_context_var();
-  context_var->set_is_forced_stack();
-  scope_->AddVariable(context_var);
-
-  parsed_function->SetNodeSequence(
-      new SequenceNode(TokenPosition::kNoSource, scope_));
-
-  switch (function.kind()) {
-    case RawFunction::kClosureFunction:
-    case RawFunction::kRegularFunction:
-    case RawFunction::kGetterFunction:
-    case RawFunction::kSetterFunction:
-    case RawFunction::kConstructor: {
-      FunctionNode* node;
-      if (node_->IsProcedure()) {
-        node = Procedure::Cast(node_)->function();
-      } else if (node_->IsConstructor()) {
-        node = Constructor::Cast(node_)->function();
-      } else {
-        node = FunctionNode::Cast(node_);
-      }
-      current_function_node_ = node;
-
-      intptr_t pos = 0;
-      if (function.IsClosureFunction()) {
-        LocalVariable* variable = MakeVariable(
-            TokenPosition::kNoSource, TokenPosition::kNoSource,
-            Symbols::ClosureParameter(), AbstractType::dynamic_type());
-        variable->set_is_forced_stack();
-        scope_->InsertParameterAt(pos++, variable);
-      } else if (!function.is_static()) {
-        // We use [is_static] instead of [IsStaticFunction] because the latter
-        // returns `false` for constructors.
-        dart::Class& klass = dart::Class::Handle(Z, function.Owner());
-        Type& klass_type = H.GetCanonicalType(klass);
-        LocalVariable* variable =
-            MakeVariable(TokenPosition::kNoSource, TokenPosition::kNoSource,
-                         Symbols::This(), klass_type);
-        scope_->InsertParameterAt(pos++, variable);
-        result_->this_variable = variable;
-
-        // We visit instance field initializers because they might contain
-        // [Let] expressions and we need to have a mapping.
-        if (node_->IsConstructor()) {
-          Class* klass = Class::Cast(Constructor::Cast(node_)->parent());
-
-          for (intptr_t i = 0; i < klass->fields().length(); i++) {
-            Field* field = klass->fields()[i];
-            if (!field->IsStatic() && (field->initializer() != NULL)) {
-              EnterScope(field, field->position());
-              field->initializer()->AcceptExpressionVisitor(this);
-              ExitScope(field->end_position());
-            }
-          }
-        }
-      } else if (function.IsFactory()) {
-        LocalVariable* variable = MakeVariable(
-            TokenPosition::kNoSource, TokenPosition::kNoSource,
-            Symbols::TypeArgumentsParameter(), AbstractType::dynamic_type());
-        scope_->InsertParameterAt(pos++, variable);
-        result_->type_arguments_variable = variable;
-      }
-      AddParameters(node, pos);
-
-      // We generate a syntethic body for implicit closure functions - which
-      // will forward the call to the real function.
-      //     -> see BuildGraphOfImplicitClosureFunction
-      if (!function.IsImplicitClosureFunction()) {
-        // TODO(jensj): HACK: Push the begin token to after any parameters to
-        // avoid crash when breaking on definition line of async method in
-        // debugger. It seems that another scope needs to be added
-        // in which captures are made, but I can't make that work.
-        // This 'solution' doesn't crash, but I cannot see the parameters at
-        // that particular breakpoint either.
-        // Also push the end token to after the "}" to avoid crashing on
-        // stepping past the last line (to the "}" character).
-        if (node->body() != NULL && node->body()->position().IsReal()) {
-          scope_->set_begin_token_pos(node->body()->position());
-        }
-        if (scope_->end_token_pos().IsReal()) {
-          scope_->set_end_token_pos(scope_->end_token_pos().Next());
-        }
-        node_->AcceptVisitor(this);
-      }
-      break;
-    }
-    case RawFunction::kImplicitGetter:
-    case RawFunction::kImplicitStaticFinalGetter:
-    case RawFunction::kImplicitSetter: {
-      ASSERT(node_->IsField());
-      if (IsStaticInitializer(function, Z)) {
-        node_->AcceptVisitor(this);
-        break;
-      }
-      bool is_setter = function.IsImplicitSetterFunction();
-      bool is_method = !function.IsStaticFunction();
-      intptr_t pos = 0;
-      if (is_method) {
-        dart::Class& klass = dart::Class::Handle(Z, function.Owner());
-        Type& klass_type = H.GetCanonicalType(klass);
-        LocalVariable* variable =
-            MakeVariable(TokenPosition::kNoSource, TokenPosition::kNoSource,
-                         Symbols::This(), klass_type);
-        scope_->InsertParameterAt(pos++, variable);
-        result_->this_variable = variable;
-      }
-      if (is_setter) {
-        result_->setter_value =
-            MakeVariable(TokenPosition::kNoSource, TokenPosition::kNoSource,
-                         Symbols::Value(), AbstractType::dynamic_type());
-        scope_->InsertParameterAt(pos++, result_->setter_value);
-      }
-      break;
-    }
-    case RawFunction::kMethodExtractor: {
-      // Add a receiver parameter.  Though it is captured, we emit code to
-      // explicitly copy it to a fixed offset in a freshly-allocated context
-      // instead of using the generic code for regular functions.
-      // Therefore, it isn't necessary to mark it as captured here.
-      dart::Class& klass = dart::Class::Handle(Z, function.Owner());
-      Type& klass_type = H.GetCanonicalType(klass);
-      LocalVariable* variable =
-          MakeVariable(TokenPosition::kNoSource, TokenPosition::kNoSource,
-                       Symbols::This(), klass_type);
-      scope_->InsertParameterAt(0, variable);
-      result_->this_variable = variable;
-      break;
-    }
-    case RawFunction::kNoSuchMethodDispatcher:
-    case RawFunction::kInvokeFieldDispatcher:
-      for (intptr_t i = 0; i < function.NumParameters(); ++i) {
-        LocalVariable* variable = MakeVariable(
-            TokenPosition::kNoSource, TokenPosition::kNoSource,
-            dart::String::ZoneHandle(Z, function.ParameterNameAt(i)),
-            AbstractType::dynamic_type());
-        scope_->InsertParameterAt(i, variable);
-      }
-      break;
-    case RawFunction::kSignatureFunction:
-    case RawFunction::kIrregexpFunction:
-      UNREACHABLE();
-  }
-  if (needs_expr_temp_) {
-    scope_->AddVariable(parsed_function_->EnsureExpressionTemp());
-  }
-  parsed_function->AllocateVariables();
-
-  return result_;
-}
-
-
-void ScopeBuilder::VisitThisExpression(ThisExpression* node) {
-  HandleSpecialLoad(&result_->this_variable, Symbols::This());
-}
-
-
-void ScopeBuilder::VisitTypeParameterType(TypeParameterType* node) {
-  Function& function = Function::Handle(Z, parsed_function_->function().raw());
-  while (function.IsClosureFunction()) {
-    function = function.parent_function();
-  }
-
-  if (function.IsFactory()) {
-    // The type argument vector is passed as the very first argument to the
-    // factory constructor function.
-    HandleSpecialLoad(&result_->type_arguments_variable,
-                      Symbols::TypeArgumentsParameter());
-  } else {
-    // The type argument vector is stored on the instance object. We therefore
-    // need to capture `this`.
-    HandleSpecialLoad(&result_->this_variable, Symbols::This());
-  }
-}
-
-
-void ScopeBuilder::VisitVariableGet(VariableGet* node) {
-  LookupVariable(node->variable());
-}
-
-
-void ScopeBuilder::VisitVariableSet(VariableSet* node) {
-  LookupVariable(node->variable());
-  node->VisitChildren(this);
-}
-
-
-void ScopeBuilder::VisitConditionalExpression(ConditionalExpression* node) {
-  needs_expr_temp_ = true;
-  node->VisitChildren(this);
-}
-
-
-void ScopeBuilder::VisitLogicalExpression(LogicalExpression* node) {
-  needs_expr_temp_ = true;
-  node->VisitChildren(this);
-}
-
-
-void ScopeBuilder::HandleLocalFunction(TreeNode* parent,
-                                       FunctionNode* function) {
-  LocalScope* saved_function_scope = current_function_scope_;
-  FunctionNode* saved_function_node = current_function_node_;
-  ScopeBuilder::DepthState saved_depth_state = depth_;
-  depth_ = DepthState(depth_.function_ + 1);
-  EnterScope(parent, function->position());
-  current_function_scope_ = scope_;
-  current_function_node_ = function;
-  if (depth_.function_ == 1) {
-    FunctionScope function_scope = {function->kernel_offset(), scope_};
-    result_->function_scopes.Add(function_scope);
-  }
-  AddParameters(function);
-  VisitFunctionNode(function);
-  ExitScope(function->end_position());
-  depth_ = saved_depth_state;
-  current_function_scope_ = saved_function_scope;
-  current_function_node_ = saved_function_node;
-}
-
-
-void ScopeBuilder::HandleSpecialLoad(LocalVariable** variable,
-                                     const dart::String& symbol) {
-  if (current_function_scope_->parent() != NULL) {
-    // We are building the scope tree of a closure function and saw [node]. We
-    // lazily populate the variable using the parent function scope.
-    if (*variable == NULL) {
-      *variable =
-          current_function_scope_->parent()->LookupVariable(symbol, true);
-      ASSERT(*variable != NULL);
-    }
-  }
-
-  if ((current_function_scope_->parent() != NULL) ||
-      (scope_->function_level() > 0)) {
-    // Every scope we use the [variable] from needs to be notified of the usage
-    // in order to ensure that preserving the context scope on that particular
-    // use-site also includes the [variable].
-    scope_->CaptureVariable(*variable);
-  }
-}
-
-
-void ScopeBuilder::VisitFunctionExpression(FunctionExpression* node) {
-  HandleLocalFunction(node, node->function());
-}
-
-
-void ScopeBuilder::VisitLet(Let* node) {
-  EnterScope(node, node->position());
-  node->VisitChildren(this);
-  ExitScope(node->end_position());
-}
-
-
-void ScopeBuilder::VisitBlock(Block* node) {
-  EnterScope(node, node->position());
-  node->VisitChildren(this);
-  ExitScope(node->end_position());
-}
-
-
-void ScopeBuilder::VisitVariableDeclaration(VariableDeclaration* node) {
-  AddVariable(node);
-  node->VisitChildren(this);
-}
-
-
-void ScopeBuilder::VisitFunctionDeclaration(FunctionDeclaration* node) {
-  VisitVariableDeclaration(node->variable());
-  HandleLocalFunction(node, node->function());
-}
-
-
-void ScopeBuilder::VisitWhileStatement(WhileStatement* node) {
-  ++depth_.loop_;
-  node->VisitChildren(this);
-  --depth_.loop_;
-}
-
-
-void ScopeBuilder::VisitDoStatement(DoStatement* node) {
-  ++depth_.loop_;
-  node->VisitChildren(this);
-  --depth_.loop_;
-}
-
-
-void ScopeBuilder::VisitForStatement(ForStatement* node) {
-  EnterScope(node, node->position());
-  List<VariableDeclaration>& variables = node->variables();
-  for (intptr_t i = 0; i < variables.length(); ++i) {
-    VisitVariableDeclaration(variables[i]);
-  }
-  ++depth_.loop_;
-  if (node->condition() != NULL) {
-    node->condition()->AcceptExpressionVisitor(this);
-  }
-  node->body()->AcceptStatementVisitor(this);
-  List<Expression>& updates = node->updates();
-  for (intptr_t i = 0; i < updates.length(); ++i) {
-    updates[i]->AcceptExpressionVisitor(this);
-  }
-  --depth_.loop_;
-  ExitScope(node->end_position());
-}
-
-
-void ScopeBuilder::VisitForInStatement(ForInStatement* node) {
-  node->iterable()->AcceptExpressionVisitor(this);
-  ++depth_.for_in_;
-  AddIteratorVariable();
-  ++depth_.loop_;
-  EnterScope(node, node->position());
-  VisitVariableDeclaration(node->variable());
-  node->body()->AcceptStatementVisitor(this);
-  ExitScope(node->end_position());
-  --depth_.loop_;
-  --depth_.for_in_;
-}
-
-
-void ScopeBuilder::AddSwitchVariable() {
-  if ((depth_.function_ == 0) && (result_->switch_variable == NULL)) {
-    LocalVariable* variable =
-        MakeVariable(TokenPosition::kNoSource, TokenPosition::kNoSource,
-                     Symbols::SwitchExpr(), AbstractType::dynamic_type());
-    variable->set_is_forced_stack();
-    current_function_scope_->AddVariable(variable);
-    result_->switch_variable = variable;
-  }
-}
-
-
-void ScopeBuilder::VisitSwitchStatement(SwitchStatement* node) {
-  AddSwitchVariable();
-  node->VisitChildren(this);
-}
-
-
-void ScopeBuilder::VisitReturnStatement(ReturnStatement* node) {
-  if ((depth_.function_ == 0) && (depth_.finally_ > 0) &&
-      (result_->finally_return_variable == NULL)) {
-    const dart::String& name = H.DartSymbol(":try_finally_return_value");
-    LocalVariable* variable =
-        MakeVariable(TokenPosition::kNoSource, TokenPosition::kNoSource, name,
-                     AbstractType::dynamic_type());
-    current_function_scope_->AddVariable(variable);
-    result_->finally_return_variable = variable;
-  }
-  node->VisitChildren(this);
-}
-
-
-void ScopeBuilder::VisitTryCatch(TryCatch* node) {
-  ++depth_.try_;
-  AddTryVariables();
-  node->body()->AcceptStatementVisitor(this);
-  --depth_.try_;
-
-  ++depth_.catch_;
-  AddCatchVariables();
-  List<Catch>& catches = node->catches();
-  for (intptr_t i = 0; i < catches.length(); ++i) {
-    Catch* ketch = catches[i];
-    EnterScope(ketch, ketch->position());
-    if (ketch->exception() != NULL) {
-      VisitVariableDeclaration(ketch->exception());
-    }
-    if (ketch->stack_trace() != NULL) {
-      VisitVariableDeclaration(ketch->stack_trace());
-    }
-    ketch->body()->AcceptStatementVisitor(this);
-    ExitScope(ketch->end_position());
-  }
-  --depth_.catch_;
-}
-
-
-void ScopeBuilder::VisitTryFinally(TryFinally* node) {
-  ++depth_.try_;
-  ++depth_.finally_;
-  AddTryVariables();
-  node->body()->AcceptStatementVisitor(this);
-  --depth_.finally_;
-  --depth_.try_;
-
-  ++depth_.catch_;
-  AddCatchVariables();
-  node->finalizer()->AcceptStatementVisitor(this);
-  --depth_.catch_;
-}
-
-
-void ScopeBuilder::VisitFunctionNode(FunctionNode* node) {
-  List<TypeParameter>& type_parameters = node->type_parameters();
-  for (intptr_t i = 0; i < type_parameters.length(); ++i) {
-    VisitTypeParameter(type_parameters[i]);
-  }
-
-  if (FLAG_causal_async_stacks &&
-      (node->dart_async_marker() == FunctionNode::kAsync ||
-       node->dart_async_marker() == FunctionNode::kAsyncStar)) {
-    LocalVariable* asyncStackTraceVar = MakeVariable(
-        TokenPosition::kNoSource, TokenPosition::kNoSource,
-        Symbols::AsyncStackTraceVar(), AbstractType::dynamic_type());
-    scope_->AddVariable(asyncStackTraceVar);
-  }
-
-  if (node->async_marker() == FunctionNode::kSyncYielding) {
-    LocalScope* scope = parsed_function_->node_sequence()->scope();
-    intptr_t offset = parsed_function_->function().num_fixed_parameters();
-    for (intptr_t i = 0;
-         i < parsed_function_->function().NumOptionalPositionalParameters();
-         i++) {
-      scope->VariableAt(offset + i)->set_is_forced_stack();
-    }
-  }
-
-  // Do not visit the positional and named parameters, because they've
-  // already been added to the scope.
-  if (node->body() != NULL) {
-    node->body()->AcceptStatementVisitor(this);
-  }
-
-  // Ensure that :await_jump_var, :await_ctx_var, :async_op and
-  // :async_stack_trace are captured.
-  if (node->async_marker() == FunctionNode::kSyncYielding) {
-    {
-      LocalVariable* temp = NULL;
-      LookupCapturedVariableByName(
-          (depth_.function_ == 0) ? &result_->yield_jump_variable : &temp,
-          Symbols::AwaitJumpVar());
-    }
-    {
-      LocalVariable* temp = NULL;
-      LookupCapturedVariableByName(
-          (depth_.function_ == 0) ? &result_->yield_context_variable : &temp,
-          Symbols::AwaitContextVar());
-    }
-    {
-      LocalVariable* temp =
-          scope_->LookupVariable(Symbols::AsyncOperation(), true);
-      if (temp != NULL) {
-        scope_->CaptureVariable(temp);
-      }
-    }
-    if (FLAG_causal_async_stacks) {
-      LocalVariable* temp =
-          scope_->LookupVariable(Symbols::AsyncStackTraceVar(), true);
-      if (temp != NULL) {
-        scope_->CaptureVariable(temp);
-      }
-    }
-  }
-}
-
-
-void ScopeBuilder::VisitYieldStatement(YieldStatement* node) {
-  ASSERT(node->is_native());
-  if (depth_.function_ == 0) {
-    AddSwitchVariable();
-    // Promote all currently visible local variables into the context.
-    // TODO(27590) CaptureLocalVariables promotes to many variables into
-    // the scope. Mark those variables as stack_local.
-    // TODO(27590) we don't need to promote those variables that are
-    // not used across yields.
-    scope_->CaptureLocalVariables(current_function_scope_);
-  }
-}
-
-
-void ScopeBuilder::VisitAssertStatement(AssertStatement* node) {
-  if (I->asserts()) {
-    RecursiveVisitor::VisitAssertStatement(node);
-  }
-}
-
-
-void ScopeBuilder::VisitConstructor(Constructor* node) {
-  // Field initializers that come from non-static field declarations are
-  // compiled as if they appear in the constructor initializer list.  This is
-  // important for closure-valued field initializers because the VM expects the
-  // corresponding closure functions to appear as if they were nested inside the
-  // constructor.
-  List<Field>& fields = Class::Cast(node->parent())->fields();
-  for (intptr_t i = 0; i < fields.length(); ++i) {
-    Field* field = fields[i];
-    Expression* initializer = field->initializer();
-    if (!field->IsStatic() && (initializer != NULL)) {
-      initializer->AcceptExpressionVisitor(this);
-    }
-  }
-  node->VisitChildren(this);
-}
-
-
 Fragment& Fragment::operator+=(const Fragment& other) {
   if (entry == NULL) {
     entry = other.entry;
@@ -3042,7 +2290,7 @@ intptr_t FlowGraphBuilder::CurrentTryIndex() {
 
 
 LocalVariable* FlowGraphBuilder::LookupVariable(VariableDeclaration* var) {
-  LocalVariable* local = scopes_->locals.Lookup(var->kernel_offset());
+  LocalVariable* local = scopes_->locals.Lookup(var->kernel_offset_no_tag());
   ASSERT(local != NULL);
   return local;
 }
@@ -3225,8 +2473,6 @@ FlowGraph* FlowGraphBuilder::BuildGraph() {
       FunctionNode* kernel_function = node_->IsProcedure()
                                           ? Procedure::Cast(node_)->function()
                                           : FunctionNode::Cast(node_);
-      ActiveFunctionScope active_function_scope(&active_class_,
-                                                kernel_function);
       return function.IsImplicitClosureFunction()
                  ? BuildGraphOfImplicitClosureFunction(kernel_function,
                                                        function)
@@ -3237,12 +2483,10 @@ FlowGraph* FlowGraphBuilder::BuildGraph() {
       if (is_factory) {
         Procedure* procedure = Procedure::Cast(node_);
         FunctionNode* function = procedure->function();
-        ActiveFunctionScope active_function_scope(&active_class_, function);
         return BuildGraphOfFunction(function, NULL);
       } else {
         Constructor* constructor = Constructor::Cast(node_);
         FunctionNode* function = constructor->function();
-        ActiveFunctionScope active_function_scope(&active_class_, function);
         return BuildGraphOfFunction(function, constructor);
       }
     }