[generators] Store the resume mode in the generator object.

src/full-codegen/x64/full-codegen-x64.cc

Index: src/full-codegen/x64/full-codegen-x64.cc
diff --git a/src/full-codegen/x64/full-codegen-x64.cc b/src/full-codegen/x64/full-codegen-x64.cc
index 94204f917bb026afb469a1f2214803a105b64fe2..24c0fac9c361c72f080f15c1a5bd312d8e959908 100644
--- a/src/full-codegen/x64/full-codegen-x64.cc
+++ b/src/full-codegen/x64/full-codegen-x64.cc
@@ -1785,11 +1785,10 @@ void FullCodeGenerator::VisitYield(Yield* expr) {
 
   __ jmp(&suspend);
   __ bind(&continuation);
-  // When we arrive here, the stack top is the resume mode and
-  // result_register() holds the input value (the argument given to the
-  // respective resume operation).
   __ RecordGeneratorContinuation();
-  __ Pop(rbx);
+  // When we arrive here, rax holds the generator object.
+  __ movp(rbx, FieldOperand(rax, JSGeneratorObject::kResumeModeOffset));
+  __ movp(rax, FieldOperand(rax, JSGeneratorObject::kInputOffset));
   STATIC_ASSERT(JSGeneratorObject::kNext < JSGeneratorObject::kReturn);
   STATIC_ASSERT(JSGeneratorObject::kThrow > JSGeneratorObject::kReturn);
   __ SmiCompare(rbx, Smi::FromInt(JSGeneratorObject::kReturn));