[arm64][Liftoff] implement stack slot allocation

Bug: v8:6600
Change-Id: I1d8447349f73985653d3124c2b76d8756b0bf30a
Reviewed-on: https://chromium-review.googlesource.com/1040673
Commit-Queue: Vincent Belliard <vincent.belliard@arm.com>
Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#52964}

src/wasm/baseline/arm64/liftoff-assembler-arm64.h

@@ -664,11 +664,16 @@ void LiftoffAssembler::CallIndirect(wasm::FunctionSig* sig,
 }
 
 void LiftoffAssembler::AllocateStackSlot(Register addr, uint32_t size) {
-  BAILOUT("AllocateStackSlot");
+  // The stack pointer is required to be quadword aligned.
+  size = RoundUp(size, kQuadWordSizeInBytes);
+  Claim(size, 1);
+  Mov(addr, sp);
 }
 
 void LiftoffAssembler::DeallocateStackSlot(uint32_t size) {
-  BAILOUT("DeallocateStackSlot");
+  // The stack pointer is required to be quadword aligned.
+  size = RoundUp(size, kQuadWordSizeInBytes);
+  Drop(size, 1);
 }
 
 void LiftoffStackSlots::Construct() {