Step #2 in streaming the kernel flowgraph

runtime/vm/kernel_binary.cc

Index: runtime/vm/kernel_binary.cc
diff --git a/runtime/vm/kernel_binary.cc b/runtime/vm/kernel_binary.cc
index 48f62684b4df816c3d5156da8a75f5b355e6f52d..1ad1089271dbab25317a288c28345d7b11f4c208 100644
--- a/runtime/vm/kernel_binary.cc
+++ b/runtime/vm/kernel_binary.cc
@@ -512,7 +512,10 @@ Expression* Expression::ReadFrom(Reader* reader) {
 
 InvalidExpression* InvalidExpression::ReadFrom(Reader* reader) {
   TRACE_READ_OFFSET();
-  return new InvalidExpression();
+  InvalidExpression* invalidExpression = new InvalidExpression();
+  invalidExpression->kernel_offset_ =
+      reader->offset() - 1;  // -1 to include tag byte.
+  return invalidExpression;
 }
 
 
@@ -742,7 +745,10 @@ AsExpression* AsExpression::ReadFrom(Reader* reader) {
 
 StringLiteral* StringLiteral::ReadFrom(Reader* reader) {
   TRACE_READ_OFFSET();
-  return new StringLiteral(Reference::ReadStringFrom(reader));
+  intptr_t offset = reader->offset() - 1;  // -1 to include tag byte.
+  StringLiteral* lit = new StringLiteral(Reference::ReadStringFrom(reader));
+  lit->kernel_offset_ = offset;
+  return lit;
 }
 
 
@@ -755,6 +761,7 @@ BigintLiteral* BigintLiteral::ReadFrom(Reader* reader) {
 IntLiteral* IntLiteral::ReadFrom(Reader* reader, bool is_negative) {
   TRACE_READ_OFFSET();
   IntLiteral* literal = new IntLiteral();
+  literal->kernel_offset_ = reader->offset() - 1;  // -1 to include tag byte.
   literal->value_ = is_negative ? -static_cast<int64_t>(reader->ReadUInt())
                                 : reader->ReadUInt();
   return literal;
@@ -764,6 +771,7 @@ IntLiteral* IntLiteral::ReadFrom(Reader* reader, bool is_negative) {
 IntLiteral* IntLiteral::ReadFrom(Reader* reader, uint8_t payload) {
   TRACE_READ_OFFSET();
   IntLiteral* literal = new IntLiteral();
+  literal->kernel_offset_ = reader->offset() - 1;  // -1 to include tag byte.
   literal->value_ = static_cast<int32_t>(payload) - SpecializedIntLiteralBias;
   return literal;
 }
@@ -780,6 +788,7 @@ DoubleLiteral* DoubleLiteral::ReadFrom(Reader* reader) {
 BoolLiteral* BoolLiteral::ReadFrom(Reader* reader, bool value) {
   TRACE_READ_OFFSET();
   BoolLiteral* lit = new BoolLiteral();
+  lit->kernel_offset_ = reader->offset() - 1;  // -1 to include tag byte.
   lit->value_ = value;
   return lit;
 }
@@ -787,7 +796,9 @@ BoolLiteral* BoolLiteral::ReadFrom(Reader* reader, bool value) {
 
 NullLiteral* NullLiteral::ReadFrom(Reader* reader) {
   TRACE_READ_OFFSET();
-  return new NullLiteral();
+  NullLiteral* lit = new NullLiteral();
+  lit->kernel_offset_ = reader->offset() - 1;  // -1 to include tag byte.
+  return lit;
 }
 
 
@@ -809,7 +820,9 @@ TypeLiteral* TypeLiteral::ReadFrom(Reader* reader) {
 
 ThisExpression* ThisExpression::ReadFrom(Reader* reader) {
   TRACE_READ_OFFSET();
-  return new ThisExpression();
+  ThisExpression* this_expr = new ThisExpression();
+  this_expr->kernel_offset_ = reader->offset() - 1;  // -1 to include tag byte.
+  return this_expr;
 }