X87: [turbofan] Add an operator to access the parent frame pointer.

  port fd8fd05c (r34014)

  original commit message:
  This functionality is useful for stubs that need to walk the stack. The new
  machine operator, LoadParentFramePointer dosn't force the currently compiling
  method to have a frame in contrast to LoadFramePointer. Instead, it adapts
  accordingly when frame elision is possible, making efficient stack walks
  possible without incurring a performance penalty for small stubs that can
  benefit from frame elision.

BUG=

Review URL: https://codereview.chromium.org/1705673002

Cr-Commit-Position: refs/heads/master@{#34064}

src/compiler/x87/code-generator-x87.cc

@@ -574,6 +574,13 @@ void CodeGenerator::AssembleArchInstruction(Instruction* instr) {
     case kArchStackPointer:
       __ mov(i.OutputRegister(), esp);
       break;
+    case kArchParentFramePointer:
+      if (frame_access_state()->frame()->needs_frame()) {
+        __ mov(i.OutputRegister(), Operand(ebp, 0));
+      } else {
+        __ mov(i.OutputRegister(), ebp);
+      }
+      break;
     case kArchTruncateDoubleToI: {
       if (!instr->InputAt(0)->IsDoubleRegister()) {
         __ fld_d(i.InputOperand(0));