Implement UnalignedLoad and UnalignedStore in WASM using LoadByte/Shift/Or and StoreByte/Shift/And.

src/compiler/arm64/instruction-selector-arm64.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/compiler/instruction-selector-impl.h"
 #include "src/compiler/node-matchers.h"
 #include "src/compiler/node-properties.h"
 
 namespace v8 {
 namespace internal {
@@ skipping 2336 matching lines @@
          MachineOperatorBuilder::kFloat64RoundTiesAway |
          MachineOperatorBuilder::kFloat32RoundTiesEven |
          MachineOperatorBuilder::kFloat64RoundTiesEven |
          MachineOperatorBuilder::kWord32ShiftIsSafe |
          MachineOperatorBuilder::kInt32DivIsSafe |
          MachineOperatorBuilder::kUint32DivIsSafe |
          MachineOperatorBuilder::kWord32ReverseBits |
          MachineOperatorBuilder::kWord64ReverseBits;
 }
 
+// static
+MachineOperatorBuilder::AlignmentRequirements
+InstructionSelector::AlignmentRequirements() {
+  return MachineOperatorBuilder::AlignmentRequirements::
+      FullUnalignedAccessSupport();
+}
+
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8