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

src/compiler/mips/instruction-selector-mips.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 1524 matching lines @@
          MachineOperatorBuilder::kFloat64Min |
          MachineOperatorBuilder::kFloat64Max |
          MachineOperatorBuilder::kFloat32Min |
          MachineOperatorBuilder::kFloat32Max |
          MachineOperatorBuilder::kFloat32RoundDown |
          MachineOperatorBuilder::kFloat32RoundUp |
          MachineOperatorBuilder::kFloat32RoundTruncate |
          MachineOperatorBuilder::kFloat32RoundTiesEven;
 }
 
+// static
+MachineOperatorBuilder::AlignmentRequirements
+InstructionSelector::AlignmentRequirements() {
+  if (IsMipsArchVariant(kMips32r6)) {
+    return MachineOperatorBuilder::AlignmentRequirements::
+        FullUnalignedAccessSupport();
+  } else {
+    DCHECK(IsMipsArchVariant(kLoongson) || IsMipsArchVariant(kMips32r1) ||
+           IsMipsArchVariant(kMips32r2));
+    return MachineOperatorBuilder::AlignmentRequirements::
+        NoUnalignedAccessSupport();
+  }
+}
+
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8