ppc: [liftoff] implement De/AllocateStackSlot

Change-Id: Iec0fdde1086b148f4be59815c48262333fd4a5dd
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3114848Reviewed-by: Milad Fa <mfarazma@redhat.com>
Commit-Queue: Junliang Yan <junyan@redhat.com>
Cr-Commit-Position: refs/heads/main@{#76439}

src/wasm/baseline/ppc/liftoff-assembler-ppc.h

@@ -2417,11 +2417,12 @@ void LiftoffAssembler::CallRuntimeStub(WasmCode::RuntimeStubId sid) {
 }
 
 void LiftoffAssembler::AllocateStackSlot(Register addr, uint32_t size) {
-  bailout(kUnsupportedArchitecture, "AllocateStackSlot");
+  SubS64(sp, sp, Operand(size), r0);
+  mr(addr, sp);
 }
 
 void LiftoffAssembler::DeallocateStackSlot(uint32_t size) {
-  bailout(kUnsupportedArchitecture, "DeallocateStackSlot");
+  AddS64(sp, sp, Operand(size));
 }
 
 void LiftoffAssembler::MaybeOSR() {}