[cfe] Add flags field to Extension and use it for 'extension type'

TEST=Checked by existing tests.

Change-Id: I436c0322124165f52195ebef402d7ab9104bbb30
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/198763
Commit-Queue: Dmitry Stefantsov <[email protected]>
Reviewed-by: Jens Johansen <[email protected]>

Author: Dmitry Stefantsov

pkg/kernel/binary.md

@@ -147,7 +147,7 @@ type CanonicalName {
 
 type ComponentFile {
   UInt32 magic = 0x90ABCDEF;
-  UInt32 formatVersion = 64;
+  UInt32 formatVersion = 65;
   Byte[10] shortSdkHash;
   List<String> problemsAsJson; // Described in problems.md.
   Library[] libraries;
@@ -343,6 +343,7 @@ type Extension extends Node {
   List<Expression> annotations;
   UriReference fileUri;
   FileOffset fileOffset;
+  Byte flags (isExtensionTypeDeclaration);
   List<TypeParameter> typeParameters;
   DartType onType;
   List<ExtensionMemberDescriptor> members;

pkg/kernel/lib/ast.dart

@@ -1522,6 +1522,11 @@ class Extension extends NamedNode implements Annotatable, FileUriNode {
   @override
   List<Expression> annotations = const <Expression>[];
 
+  // Must match serialized bit positions.
+  static const int FlagExtensionTypeDeclaration = 1 << 0;
+
+  int flags = 0;
+
   @override
   void addAnnotation(Expression node) {
     if (annotations.isEmpty) {
@@ -1553,6 +1558,16 @@ class Extension extends NamedNode implements Annotatable, FileUriNode {
 
   Library get enclosingLibrary => parent as Library;
 
+  bool get isExtensionTypeDeclaration {
+    return flags & FlagExtensionTypeDeclaration != 0;
+  }
+
+  void set isExtensionTypeDeclaration(bool value) {
+    flags = value
+        ? (flags | FlagExtensionTypeDeclaration)
+        : (flags & ~FlagExtensionTypeDeclaration);
+  }
+
   @override
   R accept<R>(TreeVisitor<R> v) => v.visitExtension(this);
 

pkg/kernel/lib/binary/ast_from_binary.dart

@@ -1416,6 +1416,8 @@ class BinaryBuilder {
 
     node.fileOffset = readOffset();
 
+    node.flags = readByte();
+
     readAndPushTypeParameterList(node.typeParameters, node);
     DartType onType = readDartType();
     typeParameterStack.length = 0;

pkg/kernel/lib/binary/ast_to_binary.dart

@@ -2436,6 +2436,7 @@ class BinaryPrinter implements Visitor<void>, BinarySink {
     writeAnnotationList(node.annotations);
     writeUriReference(node.fileUri);
     writeOffset(node.fileOffset);
+    writeByte(node.flags);
 
     enterScope(typeParameters: node.typeParameters);
     writeNodeList(node.typeParameters);

pkg/kernel/lib/binary/tag.dart

@@ -174,7 +174,7 @@ class Tag {
   /// Internal version of kernel binary format.
   /// Bump it when making incompatible changes in kernel binaries.
   /// Keep in sync with runtime/vm/kernel_binary.h, pkg/kernel/binary.md.
-  static const int BinaryFormatVersion = 64;
+  static const int BinaryFormatVersion = 65;
 }
 
 abstract class ConstantTag {

pkg/kernel/lib/text/ast_to_text.dart

@@ -1337,6 +1337,9 @@ class Printer extends Visitor<void> with VisitorVoidMixin {
     writeAnnotationList(node.annotations);
     writeIndentation();
     writeWord('extension');
+    if (node.isExtensionTypeDeclaration) {
+      writeWord('type');
+    }
     writeWord(getExtensionName(node));
     writeTypeParameterList(node.typeParameters);
     writeSpaced('on');

runtime/vm/kernel_binary.h

@@ -20,8 +20,8 @@ namespace kernel {
 static const uint32_t kMagicProgramFile = 0x90ABCDEFu;
 
 // Both version numbers are inclusive.
-static const uint32_t kMinSupportedKernelFormatVersion = 64;
-static const uint32_t kMaxSupportedKernelFormatVersion = 64;
+static const uint32_t kMinSupportedKernelFormatVersion = 65;
+static const uint32_t kMaxSupportedKernelFormatVersion = 65;
 
 // Keep in sync with package:kernel/lib/binary/tag.dart
 #define KERNEL_TAG_LIST(V)                                                     \

runtime/vm/kernel_loader.cc

@@ -1187,6 +1187,7 @@ void KernelLoader::FinishTopLevelClassLoading(
       helper_.SkipListOfExpressions();       // skip annotations.
       helper_.ReadUInt();                    // read source uri index.
       helper_.ReadPosition();                // read file offset.
+      helper_.ReadByte();                    // skip flags.
       helper_.SkipTypeParametersList();      // skip type parameter list.
       helper_.SkipDartType();                // skip on-type.