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

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

Index: src/compiler/ppc/code-generator-ppc.cc
diff --git a/src/compiler/ppc/code-generator-ppc.cc b/src/compiler/ppc/code-generator-ppc.cc
index 174e0c11ae1ff9f757bbb7fc839094a2a8fb3f1f..e639a9247fa3f54856ddcd1fae81d7f5b579383a 100644
--- a/src/compiler/ppc/code-generator-ppc.cc
+++ b/src/compiler/ppc/code-generator-ppc.cc
@@ -821,6 +821,13 @@ void CodeGenerator::AssembleArchInstruction(Instruction* instr) {
       __ mr(i.OutputRegister(), fp);
       DCHECK_EQ(LeaveRC, i.OutputRCBit());
       break;
+    case kArchParentFramePointer:
+      if (frame_access_state()->frame()->needs_frame()) {
+        __ LoadP(i.OutputRegister(), MemOperand(fp, 0));
+      } else {
+        __ mr(i.OutputRegister(), fp);
+      }
+      break;
     case kArchTruncateDoubleToI:
       // TODO(mbrandy): move slow call to stub out of line.
       __ TruncateDoubleToI(i.OutputRegister(), i.InputDoubleRegister(0));