Hacky streaming of VariableGet

pkg/kernel/lib/binary/ast_to_binary.dart

Index: pkg/kernel/lib/binary/ast_to_binary.dart
diff --git a/pkg/kernel/lib/binary/ast_to_binary.dart b/pkg/kernel/lib/binary/ast_to_binary.dart
index 2c87df570979b7c95ebca030b559d3357531f6bd..7a8980ecbf56a455c4007f9c9499c06c4cf8aeae 100644
--- a/pkg/kernel/lib/binary/ast_to_binary.dart
+++ b/pkg/kernel/lib/binary/ast_to_binary.dart
@@ -393,7 +393,7 @@ class BinaryPrinter extends Visitor {
 
   visitLocalInitializer(LocalInitializer node) {
     writeByte(Tag.LocalInitializer);
-    writeVariableDeclaration(node.variable);
+    writeVariableDeclaration(node.variable, false);
   }
 
   visitFunctionNode(FunctionNode node) {
@@ -433,9 +433,11 @@ class BinaryPrinter extends Visitor {
         node.promotedType == null) {
       writeByte(Tag.SpecializedVariableGet + index);
       writeOffset(node.fileOffset);
+      writeUInt30(node.variable.tempOffset);
     } else {
       writeByte(Tag.VariableGet);
       writeOffset(node.fileOffset);
+      writeUInt30(node.variable.tempOffset);
       writeUInt30(_variableIndexer[node.variable]);
       writeOptionalNode(node.promotedType);
     }
@@ -713,7 +715,7 @@ class BinaryPrinter extends Visitor {
 
   visitLet(Let node) {
     writeByte(Tag.Let);
-    writeVariableDeclaration(node.variable);
+    writeVariableDeclaration(node.variable, false);
     writeNode(node.body);
     --_variableIndexer.stackHeight;
   }
@@ -824,7 +826,7 @@ class BinaryPrinter extends Visitor {
     _variableIndexer.pushScope();
     writeByte(node.isAsync ? Tag.AsyncForInStatement : Tag.ForInStatement);
     writeOffset(node.fileOffset);
-    writeVariableDeclaration(node.variable);
+    writeVariableDeclaration(node.variable, false);
     writeNode(node.iterable);
     writeNode(node.body);
     _variableIndexer.popScope();
@@ -895,10 +897,13 @@ class BinaryPrinter extends Visitor {
 
   visitVariableDeclaration(VariableDeclaration node) {
     writeByte(Tag.VariableDeclaration);
-    writeVariableDeclaration(node);
+    writeVariableDeclaration(node, true);
   }
 
-  void writeVariableDeclaration(VariableDeclaration node) {
+  void writeVariableDeclaration(VariableDeclaration node,
+      [bool hasTag = false]) {
+    int length = _sink.flushedLength + _sink.length - (hasTag ? 1 : 0);

[Kevin Millikin (Google), 2017/04/05 08:59:57]

It seems better to move writing of the tag here so you have something like:

node.binaryPosition = ...;
if (hasTag) writeByte(Tag.VariableDeclaration);
writeOffset(node.fileOffset);
...

+    node.tempOffset = length;
     writeOffset(node.fileOffset);
     writeOffset(node.fileEqualsOffset);
     writeByte(node.flags);
@@ -919,14 +924,14 @@ class BinaryPrinter extends Visitor {
       writeByte(Tag.Nothing);
     } else {
       writeByte(Tag.Something);
-      writeVariableDeclaration(node);
+      writeVariableDeclaration(node, false);
     }
   }
 
   visitFunctionDeclaration(FunctionDeclaration node) {
     writeByte(Tag.FunctionDeclaration);
     writeOffset(node.fileOffset);
-    writeVariableDeclaration(node.variable);
+    writeVariableDeclaration(node.variable, false);
     writeNode(node.function);
   }
 
@@ -1252,6 +1257,7 @@ class BufferedSink {
   final Sink<List<int>> _sink;
   Uint8List _buffer = new Uint8List(SIZE);
   int length = 0;
+  int flushedLength = 0;
 
   BufferedSink(this._sink);
 
@@ -1261,6 +1267,7 @@ class BufferedSink {
       _sink.add(_buffer);
       _buffer = new Uint8List(SIZE);
       length = 0;
+      flushedLength += SIZE;
     }
   }
 
@@ -1271,6 +1278,7 @@ class BufferedSink {
         (bytes.length < SMALL || length < SMALL)) {
       if (length == 0) {
         _sink.add(bytes);
+        flushedLength += bytes.length;
       } else {
         _buffer.setRange(length, length + bytes.length, bytes);
         length += bytes.length;
@@ -1286,10 +1294,13 @@ class BufferedSink {
       _buffer = new Uint8List(SIZE);
       _buffer.setRange(0, remainder, bytes, alreadyEmitted);
       length = remainder;
+      flushedLength += SIZE;
     } else {
       _sink.add(_buffer.sublist(0, length));
       _sink.add(bytes);
       _buffer = new Uint8List(SIZE);
+      flushedLength += length;
+      flushedLength += bytes.length;
       length = 0;
     }
   }
@@ -1297,6 +1308,7 @@ class BufferedSink {
   void flush() {
     _sink.add(_buffer.sublist(0, length));
     _buffer = new Uint8List(SIZE);
+    flushedLength += length;
     length = 0;
   }