[WebAssembly] Remove unused function return types (NFC)

lib/MC/WasmObjectWriter.cpp

private:
 
   uint32_t getProvisionalValue(const WasmRelocationEntry &RelEntry);
   void applyRelocations(ArrayRef<WasmRelocationEntry> Relocations,
                         uint64_t ContentsOffset);
 
   uint32_t getRelocationIndexValue(const WasmRelocationEntry &RelEntry);
   uint32_t getFunctionType(const MCSymbolWasm &Symbol);
   uint32_t getEventType(const MCSymbolWasm &Symbol);
-  uint32_t registerFunctionType(const MCSymbolWasm &Symbol);
-  uint32_t registerEventType(const MCSymbolWasm &Symbol);
+  void registerFunctionType(const MCSymbolWasm &Symbol);
+  void registerEventType(const MCSymbolWasm &Symbol);
 };
 
 } // end anonymous namespace
 
 WasmObjectWriter::~WasmObjectWriter() {}
 
 // Write out a section header and a patchable section size field.
 void WasmObjectWriter::startSection(SectionBookkeeping &Section,

 }
 
 uint32_t WasmObjectWriter::getEventType(const MCSymbolWasm &Symbol) {
   assert(Symbol.isEvent());
   assert(TypeIndices.count(&Symbol));
   return TypeIndices[&Symbol];
 }
 
-uint32_t WasmObjectWriter::registerFunctionType(const MCSymbolWasm &Symbol) {
+void WasmObjectWriter::registerFunctionType(const MCSymbolWasm &Symbol) {
   assert(Symbol.isFunction());
 
   WasmSignature S;
   const MCSymbolWasm *ResolvedSym = ResolveSymbol(Symbol);
   if (auto *Sig = ResolvedSym->getSignature()) {
     S.Returns = Sig->Returns;
     S.Params = Sig->Params;
   }
 
   auto Pair = SignatureIndices.insert(std::make_pair(S, Signatures.size()));
   if (Pair.second)
     Signatures.push_back(S);
   TypeIndices[&Symbol] = Pair.first->second;
 
   LLVM_DEBUG(dbgs() << "registerFunctionType: " << Symbol
                     << " new:" << Pair.second << "\n");
   LLVM_DEBUG(dbgs() << "  -> type index: " << Pair.first->second << "\n");
-  return Pair.first->second;
 }
 
-uint32_t WasmObjectWriter::registerEventType(const MCSymbolWasm &Symbol) {
+void WasmObjectWriter::registerEventType(const MCSymbolWasm &Symbol) {
   assert(Symbol.isEvent());
 
   // TODO Currently we don't generate imported exceptions, but if we do, we
   // should have a way of infering types of imported exceptions.
   WasmSignature S;
   if (auto *Sig = Symbol.getSignature()) {
     S.Returns = Sig->Returns;
     S.Params = Sig->Params;
   }
 
   auto Pair = SignatureIndices.insert(std::make_pair(S, Signatures.size()));
   if (Pair.second)
     Signatures.push_back(S);
   TypeIndices[&Symbol] = Pair.first->second;
 
   LLVM_DEBUG(dbgs() << "registerEventType: " << Symbol << " new:" << Pair.second
                     << "\n");
   LLVM_DEBUG(dbgs() << "  -> type index: " << Pair.first->second << "\n");
-  return Pair.first->second;
 }
 
 static bool isInSymtab(const MCSymbolWasm &Sym) {
   if (Sym.isUsedInReloc())
     return true;
 
   if (Sym.isComdat() && !Sym.isDefined())
     return false;