[turbofan] Reland of `Add alignment parameter to StackSlot operator`

src/compiler/arm64/instruction-selector-arm64.cc

Index: src/compiler/arm64/instruction-selector-arm64.cc
diff --git a/src/compiler/arm64/instruction-selector-arm64.cc b/src/compiler/arm64/instruction-selector-arm64.cc
index d9f972e81ccb34ef5154940e248f74d9ddb6dd6f..0e9fd0ca2b548d963e24bdbd9cfbba7a9e7646a2 100644
--- a/src/compiler/arm64/instruction-selector-arm64.cc
+++ b/src/compiler/arm64/instruction-selector-arm64.cc
@@ -527,6 +527,15 @@ int32_t LeftShiftForReducedMultiply(Matcher* m) {
 
 }  // namespace
 
+void InstructionSelector::VisitStackSlot(Node* node) {
+  StackSlotRepresentation rep = StackSlotRepresentationOf(node->op());
+  int slot = frame_->AllocateSpillSlot(rep.size());
+  OperandGenerator g(this);
+
+  Emit(kArchStackSlot, g.DefineAsRegister(node),
+       sequence()->AddImmediate(Constant(slot)), 0, nullptr);
+}
+
 void EmitLoad(InstructionSelector* selector, Node* node, InstructionCode opcode,
               ImmediateMode immediate_mode, MachineRepresentation rep,
               Node* output = nullptr) {