Save/restore only live registers in the generator suspend/resume.

src/compiler/bytecode-graph-builder.cc

Index: src/compiler/bytecode-graph-builder.cc
diff --git a/src/compiler/bytecode-graph-builder.cc b/src/compiler/bytecode-graph-builder.cc
index 14c97c832f18c2e9aa329f44c3e7838c6f31bfd3..513e9ce10d5299b62ff8599375f441bbbd1b20de 100644
--- a/src/compiler/bytecode-graph-builder.cc
+++ b/src/compiler/bytecode-graph-builder.cc
@@ -2277,15 +2277,20 @@ void BytecodeGraphBuilder::VisitSuspendGenerator() {
   Node* state = environment()->LookupAccumulator();
   Node* generator = environment()->LookupRegister(
       bytecode_iterator().GetRegisterOperand(0));
+  interpreter::Register first_reg = bytecode_iterator().GetRegisterOperand(1);
+  // We assume we are storing a range starting from index 0.
+  CHECK_EQ(0, first_reg.index());
+  int register_count =
+      static_cast<int>(bytecode_iterator().GetRegisterCountOperand(2));
   SuspendFlags flags = interpreter::SuspendGeneratorBytecodeFlags::Decode(
-      bytecode_iterator().GetFlagOperand(1));
+      bytecode_iterator().GetFlagOperand(3));
+
   // The offsets used by the bytecode iterator are relative to a different base
   // than what is used in the interpreter, hence the addition.
   Node* offset =
       jsgraph()->Constant(bytecode_iterator().current_offset() +
                           (BytecodeArray::kHeaderSize - kHeapObjectTag));
 
-  int register_count = environment()->register_count();
   int value_input_count = 3 + register_count;
 
   Node** value_inputs = local_zone()->NewArray<Node*>(value_input_count);
@@ -2305,9 +2310,26 @@ void BytecodeGraphBuilder::VisitResumeGenerator() {
   Node* generator = environment()->LookupRegister(
       bytecode_iterator().GetRegisterOperand(0));
 
+  Node* state =
+      NewNode(javascript()->GeneratorRestoreContinuation(), generator);
+
+  environment()->BindAccumulator(state, Environment::kAttachFrameState);
+}
+
+void BytecodeGraphBuilder::VisitRestoreGeneratorRegisters() {
+  PrepareEagerCheckpoint();
+
+  Node* generator =
+      environment()->LookupRegister(bytecode_iterator().GetRegisterOperand(0));
+  interpreter::Register first_reg = bytecode_iterator().GetRegisterOperand(1);
+  // We assume we are restoring registers starting fromm index 0.
+  CHECK_EQ(0, first_reg.index());
+  int register_count =
+      static_cast<int>(bytecode_iterator().GetRegisterCountOperand(2));
+
   // Bijection between registers and array indices must match that used in
   // InterpreterAssembler::ExportRegisterFile.
-  for (int i = 0; i < environment()->register_count(); ++i) {
+  for (int i = 0; i < register_count; ++i) {
     Node* value = NewNode(javascript()->GeneratorRestoreRegister(i), generator);
     environment()->BindRegister(interpreter::Register(i), value);
   }