[wasm] Remove some small TODOs and small fixes.

src/wasm/wasm-opcodes.cc

 // Copyright 2015 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/wasm/wasm-opcodes.h"
 
 #include <array>
 
 #include "src/base/template-utils.h"
 #include "src/messages.h"
@@ skipping 381 matching lines @@
   DCHECK_GT(kSimpleAsmjsExprSigTable.size(), opcode);
   return const_cast<FunctionSig*>(
       kSimpleExprSigs[kSimpleAsmjsExprSigTable[opcode]]);
 }
 
 FunctionSig* WasmOpcodes::AtomicSignature(WasmOpcode opcode) {
   return const_cast<FunctionSig*>(
       kSimpleExprSigs[kAtomicExprSigTable[opcode & 0xff]]);
 }
 
-// TODO(titzer): pull WASM_64 up to a common header.
-#if !V8_TARGET_ARCH_32_BIT || V8_TARGET_ARCH_X64
-#define WASM_64 1
-#else
-#define WASM_64 0
-#endif
-
 int WasmOpcodes::TrapReasonToMessageId(TrapReason reason) {
   switch (reason) {
 #define TRAPREASON_TO_MESSAGE(name) \
   case k##name:                     \
     return MessageTemplate::kWasm##name;
     FOREACH_WASM_TRAPREASON(TRAPREASON_TO_MESSAGE)
 #undef TRAPREASON_TO_MESSAGE
     default:
       return MessageTemplate::kNone;
   }
 }
 
 const char* WasmOpcodes::TrapReasonMessage(TrapReason reason) {
   return MessageTemplate::TemplateString(TrapReasonToMessageId(reason));
 }
 }  // namespace wasm
 }  // namespace internal
 }  // namespace v8