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

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

Index: src/compiler/arm/code-generator-arm.cc
diff --git a/src/compiler/arm/code-generator-arm.cc b/src/compiler/arm/code-generator-arm.cc
index 8e1dcf8e4902fe840b5729e7fdff857c8ff50d2d..961cfb40526dcbf853e006811c70bb4d1b1e0dd5 100644
--- a/src/compiler/arm/code-generator-arm.cc
+++ b/src/compiler/arm/code-generator-arm.cc
@@ -533,6 +533,13 @@ void CodeGenerator::AssembleArchInstruction(Instruction* instr) {
       __ mov(i.OutputRegister(), fp);
       DCHECK_EQ(LeaveCC, i.OutputSBit());
       break;
+    case kArchParentFramePointer:
+      if (frame_access_state()->frame()->needs_frame()) {
+        __ ldr(i.OutputRegister(), MemOperand(fp, 0));
+      } else {
+        __ mov(i.OutputRegister(), fp);
+      }
+      break;
     case kArchTruncateDoubleToI:
       __ TruncateDoubleToI(i.OutputRegister(), i.InputFloat64Register(0));
       DCHECK_EQ(LeaveCC, i.OutputSBit());