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

src/compiler/mips64/code-generator-mips64.cc

Index: src/compiler/mips64/code-generator-mips64.cc
diff --git a/src/compiler/mips64/code-generator-mips64.cc b/src/compiler/mips64/code-generator-mips64.cc
index e4560c3843b73a07ac3fd667adb4ebfcd007dfac..d2140b5dab44ad666d4abbce7ad20d154ae5520f 100644
--- a/src/compiler/mips64/code-generator-mips64.cc
+++ b/src/compiler/mips64/code-generator-mips64.cc
@@ -614,6 +614,13 @@ void CodeGenerator::AssembleArchInstruction(Instruction* instr) {
     case kArchFramePointer:
       __ mov(i.OutputRegister(), fp);
       break;
+    case kArchParentFramePointer:
+      if (frame_access_state()->frame()->needs_frame()) {
+        __ lw(i.OutputRegister(), MemOperand(fp, 0));
+      } else {
+        __ mov(i.OutputRegister(), fp);
+      }
+      break;
     case kArchTruncateDoubleToI:
       __ TruncateDoubleToI(i.OutputRegister(), i.InputDoubleRegister(0));
       break;