Hacky streaming of VariableGet

runtime/vm/kernel_binary_flowgraph.cc

Index: runtime/vm/kernel_binary_flowgraph.cc
diff --git a/runtime/vm/kernel_binary_flowgraph.cc b/runtime/vm/kernel_binary_flowgraph.cc
index 3fdd7a26aba7510267d8ee8b9e0e6a81561bb2f8..000edc55b485c995654244c0cfd2bfe521015c47 100644
--- a/runtime/vm/kernel_binary_flowgraph.cc
+++ b/runtime/vm/kernel_binary_flowgraph.cc
@@ -214,10 +214,10 @@ Fragment StreamingFlowGraphBuilder::BuildAt(intptr_t kernel_offset) {
   switch (tag) {
     case kInvalidExpression:
       return BuildInvalidExpression();
-    //    case kVariableGet:
-    //      return VariableGet::ReadFrom(reader_);
-    //    case kSpecializedVariableGet:
-    //      return VariableGet::ReadFrom(reader_, payload);
+    case kVariableGet:
+      return BuildVariableGet();
+    case kSpecializedVariableGet:
+      return BuildVariableGet(payload);
     //    case kVariableSet:
     //      return VariableSet::ReadFrom(reader_);
     //    case kSpecializedVariableSet:
@@ -483,6 +483,11 @@ String* StreamingFlowGraphBuilder::KernelString(intptr_t str_index) {
   return new String(data, bytes);
 }
 
+dart::LocalVariable* StreamingFlowGraphBuilder::LookupVariable(
+    intptr_t kernel_offset) {
+  return flow_graph_builder_->LookupVariable(kernel_offset);
+}
+
 Fragment StreamingFlowGraphBuilder::DebugStepCheck(TokenPosition position) {
   return flow_graph_builder_->DebugStepCheck(position);
 }
@@ -529,6 +534,27 @@ Fragment StreamingFlowGraphBuilder::BuildInvalidExpression() {
   return ThrowNoSuchMethodError();
 }
 
+Fragment StreamingFlowGraphBuilder::BuildVariableGet() {
+  ReadPosition();
+  intptr_t variable_kernel_position = ReadUInt();
+  ReadUInt();  // Variable index.
+
+  // TODO(jensj): This is actually a "reader->ReadOptional<DartType>();".
+  // Optional type below: Not currently implemented.
+  Tag tag = ReadTag();
+  if (tag != kNothing) {
+    UNIMPLEMENTED();
+  }
+
+  return LoadLocal(LookupVariable(variable_kernel_position));
+}
+
+Fragment StreamingFlowGraphBuilder::BuildVariableGet(uint8_t payload) {
+  ReadPosition();
+  intptr_t variable_kernel_position = ReadUInt();
+  return LoadLocal(LookupVariable(variable_kernel_position));
+}
+
 Fragment StreamingFlowGraphBuilder::BuildStaticGet() {
   intptr_t saved_offset = ReaderOffset() - 1;  // Include the tag.
   TokenPosition position = ReadPosition();