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

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

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/base/adapters.h"
 #include "src/base/bits.h"
 #include "src/compiler/instruction-selector-impl.h"
 #include "src/compiler/node-matchers.h"
 #include "src/compiler/node-properties.h"
 
@@ skipping 401 matching lines @@
     input_count = 4;
   } else {
     inputs[input_count++] = g.UseRegister(index);
     opcode |= AddressingModeField::encode(kMode_Offset_RR);
   }
   selector->Emit(opcode, 0, nullptr, input_count, inputs);
 }
 
 }  // 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 InstructionSelector::VisitLoad(Node* node) {
   LoadRepresentation load_rep = LoadRepresentationOf(node->op());
   ArmOperandGenerator g(this);
   Node* base = node->InputAt(0);
   Node* index = node->InputAt(1);
 
   InstructionCode opcode = kArchNop;
   switch (load_rep.representation()) {
     case MachineRepresentation::kFloat32:
@@ skipping 2388 matching lines @@
   Vector<MachineType> req_aligned = Vector<MachineType>::New(2);
   req_aligned[0] = MachineType::Float32();
   req_aligned[1] = MachineType::Float64();
   return MachineOperatorBuilder::AlignmentRequirements::
       SomeUnalignedAccessUnsupported(req_aligned, req_aligned);
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8