Add IR nodes needed for deferred loading.

pkg/kernel/lib/binary/ast_to_binary.dart

 // Copyright (c) 2016, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 library kernel.ast_to_binary;
 
 import '../ast.dart';
 import '../import_table.dart';
 import 'tag.dart';
 import 'dart:convert';
 import 'dart:typed_data';
 import 'dart:collection';
 
 /// Writes to a binary file.
 ///
 /// A [BinaryPrinter] can be used to write one file and must then be
 /// discarded.
 class BinaryPrinter extends Visitor {
   ImportTable _importTable;
 
   VariableIndexer _variableIndexer;
   LabelIndexer _labelIndexer;
   SwitchCaseIndexer _switchCaseIndexer;
   final TypeParameterIndexer _typeParameterIndexer = new TypeParameterIndexer();
   final GlobalIndexer _globalIndexer;
   final StringIndexer _stringIndexer = new StringIndexer();
   final StringIndexer _sourceUriIndexer = new StringIndexer();
+  Map<DeferredImport, int> _deferredImportIndexer = <DeferredImport, int>{};
 
   final BufferedSink _sink;
 
   /// Create a printer that writes to the given [sink].
   ///
   /// The BinaryPrinter will use its own buffer, so the [sink] does not need
   /// one.
   ///
   /// If multiple binaries are to be written based on the same IR, a shared
   /// [globalIndexer] may be passed in to avoid rebuilding the same indices
@@ skipping 131 matching lines @@
   }
 
   void writeLibraryReference(Library node) {
     int index = _importTable.getImportIndex(node);
     if (index == -1) {
       throw 'Missing import for library: ${node.importUri}';
     }
     writeUInt30(index);
   }
 
+  void writeDeferredImportReference(DeferredImport node) {
+    int index = _deferredImportIndexer[node];
+    if (index == null) {
+      throw 'Reference to deferred import $node out of scope';
+    }
+    writeUInt30(index);
+  }
+
   void writeClassIndex(Class node) {
     writeUInt30(_globalIndexer[node]);
   }
 
   void writeClassReference(Class node, {bool allowNull: false}) {
     if (node == null) {
       if (allowNull) {
         writeByte(Tag.NullReference);
       } else {
         throw 'Expected a class reference to be valid but was `null`.';
@@ skipping 74 matching lines @@
 
   bool insideExternalLibrary = false;
 
   visitLibrary(Library node) {
     insideExternalLibrary = node.isExternal;
     writeByte(insideExternalLibrary ? 1 : 0);
     writeStringReference(node.name ?? '');
     writeStringReference('${node.importUri}');
     // TODO(jensj): We save (almost) the same URI twice.
     writeUriReference(node.fileUri ?? '');
+    writeDeferredImports(node);
     writeNodeList(node.classes);
     writeNodeList(node.fields);
     writeNodeList(node.procedures);
   }
 
+  void writeDeferredImports(Library library) {
+    _deferredImportIndexer = library.deferredImports.isEmpty
+        ? const <DeferredImport, int>{}
+        : <DeferredImport, int>{};
+    writeUInt30(library.deferredImports.length);
+    for (int i = 0; i < library.deferredImports.length; ++i) {
+      var importNode = library.deferredImports[i];
+      _deferredImportIndexer[importNode] = i;
+      writeDeferredImport(importNode);
+    }
+  }
+
+  void writeDeferredImport(DeferredImport node) {
+    writeLibraryReference(node.importedLibrary);
+    writeStringReference(node.name);
+  }
+
   void writeAnnotation(Expression annotation) {
     _variableIndexer ??= new VariableIndexer();
     writeNode(annotation);
   }
 
   void writeAnnotationList(List<Expression> annotations) {
     writeList(annotations, writeAnnotation);
   }
 
   visitClass(Class node) {
@@ skipping 418 matching lines @@
     writeNode(node.function);
   }
 
   visitLet(Let node) {
     writeByte(Tag.Let);
     writeVariableDeclaration(node.variable);
     writeNode(node.body);
     --_variableIndexer.stackHeight;
   }
 
+  visitLoadLibrary(LoadLibrary node) {
+    writeByte(Tag.LoadLibrary);
+    writeDeferredImportReference(node.import);
+  }
+
+  visitCheckLibraryIsLoaded(CheckLibraryIsLoaded node) {
+    writeByte(Tag.CheckLibraryIsLoaded);
+    writeDeferredImportReference(node.import);
+  }
+
   writeStatementOrEmpty(Statement node) {
     if (node == null) {
       writeByte(Tag.EmptyStatement);
     } else {
       writeNode(node);
     }
   }
 
   visitInvalidStatement(InvalidStatement node) {
     writeByte(Tag.InvalidStatement);
@@ skipping 366 matching lines @@
   visitName(Name node) {
     put(node.name);
   }
 
   visitLibrary(Library node) {
     putOptional(node.name);
     put('${node.importUri}');
     node.visitChildren(this);
   }
 
+  visitDeferredImport(DeferredImport node) {
+    put(node.name);
+  }
+
   visitClass(Class node) {
     putOptional(node.name);
     node.visitChildren(this);
   }
 
   visitNamedExpression(NamedExpression node) {
     put(node.name);
     node.visitChildren(this);
   }
 
@@ skipping 130 matching lines @@
   void flush() {
     _sink.add(_buffer.sublist(0, length));
     _buffer = new Uint8List(SIZE);
     length = 0;
   }
 
   void flushAndDestroy() {
     _sink.add(_buffer.sublist(0, length));
   }
 }