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

src/interpreter/bytecode-generator.h

Index: src/interpreter/bytecode-generator.h
diff --git a/src/interpreter/bytecode-generator.h b/src/interpreter/bytecode-generator.h
index 579365952b9fae9bd4fc51e4c902c0b8bd0c4133..cba0a5eef1cc8878855e9fb1bd83c1217d8dc06e 100644
--- a/src/interpreter/bytecode-generator.h
+++ b/src/interpreter/bytecode-generator.h
@@ -136,8 +136,10 @@ class BytecodeGenerator final : public AstVisitor<BytecodeGenerator> {
   void BuildNewLocalWithContext(Scope* scope);
 
   void BuildGeneratorPrologue();
-  void BuildGeneratorSuspend(Suspend* expr, Register generator);
-  void BuildGeneratorResume(Suspend* expr, Register generator);
+  void BuildGeneratorSuspend(Suspend* expr, Register generator,
+                             RegisterList registers_to_save);
+  void BuildGeneratorResume(Suspend* expr, Register generator,
+                            RegisterList registers_to_restore);
 
   void VisitArgumentsObject(Variable* variable);
   void VisitRestArgumentsArray(Variable* rest);
@@ -256,6 +258,7 @@ class BytecodeGenerator final : public AstVisitor<BytecodeGenerator> {
   ExpressionResultScope* execution_result_;
 
   BytecodeJumpTable* generator_jump_table_;
+  Register generator_object_;
   Register generator_state_;
   int loop_depth_;
 };