[turbofan] Add an operator to access the parent frame pointer

src/compiler/x64/code-generator-x64.cc

Index: src/compiler/x64/code-generator-x64.cc
diff --git a/src/compiler/x64/code-generator-x64.cc b/src/compiler/x64/code-generator-x64.cc
index 579e6b8ebad88bf628187a09d2cdf1844faf3e96..be1c228b01ed525f4c03953192e8e8eeab853e16 100644
--- a/src/compiler/x64/code-generator-x64.cc
+++ b/src/compiler/x64/code-generator-x64.cc
@@ -712,6 +712,13 @@ void CodeGenerator::AssembleArchInstruction(Instruction* instr) {
     case kArchFramePointer:
       __ movq(i.OutputRegister(), rbp);
       break;
+    case kArchParentFramePointer:
+      if (frame_access_state()->frame()->needs_frame()) {
+        __ movq(i.OutputRegister(), Operand(rbp, 0));
+      } else {
+        __ movq(i.OutputRegister(), rbp);
+      }
+      break;
     case kArchTruncateDoubleToI: {
       auto result = i.OutputRegister();
       auto input = i.InputDoubleRegister(0);