[WebAssembly] Reduce code repetition. NFC.

[ruiu]

Summary

[WebAssembly] Reduce code repetition. NFC.

wasm/SymbolTable.cpp

static void checkDataType(const Symbol *Existing, const InputFile *File) {
   if (!isa<DataSymbol>(Existing))
     reportTypeError(Existing, File, "Data");
 }
 
 DefinedFunction *SymbolTable::addSyntheticFunction(StringRef Name,
                                                    const WasmSignature *Type,
                                                    uint32_t Flags) {
   DEBUG(dbgs() << "addSyntheticFunction: " << Name << "\n");
-  Symbol *S;
-  bool WasInserted;
-  std::tie(S, WasInserted) = insert(Name);
-  assert(WasInserted);
-  return replaceSymbol<DefinedFunction>(S, Name, Flags, Type);
+  assert(!find(Name));
+  return replaceSymbol<DefinedFunction>(insert(Name).first, Name, Flags, Type);
 }
 
 DefinedData *SymbolTable::addSyntheticDataSymbol(StringRef Name,
                                                  uint32_t Flags) {
   DEBUG(dbgs() << "addSyntheticDataSymbol: " << Name << "\n");
-  Symbol *S;
-  bool WasInserted;
-  std::tie(S, WasInserted) = insert(Name);
-  assert(WasInserted);
-  return replaceSymbol<DefinedData>(S, Name, Flags);
+  assert(!find(Name));
+  return replaceSymbol<DefinedData>(insert(Name).first, Name, Flags);
 }
 
 DefinedGlobal *SymbolTable::addSyntheticGlobal(StringRef Name, uint32_t Flags,
                                                InputGlobal *Global) {
   DEBUG(dbgs() << "addSyntheticGlobal: " << Name << " -> " << Global << "\n");
-  Symbol *S;
-  bool WasInserted;
-  std::tie(S, WasInserted) = insert(Name);
-  assert(WasInserted);
-  return replaceSymbol<DefinedGlobal>(S, Name, Flags, nullptr, Global);
+  assert(!find(Name));
+  return replaceSymbol<DefinedGlobal>(insert(Name).first, Name, Flags, nullptr,
+                                      Global);
 }
 
 static bool shouldReplace(const Symbol *Existing, InputFile *NewFile,
                           uint32_t NewFlags) {
   // If existing symbol is undefined, replace it.
   if (!Existing->isDefined()) {
     DEBUG(dbgs() << "resolving existing undefined symbol: "
                  << Existing->getName() << "\n");
Symbol *SymbolTable::addUndefinedFunction(StringRef Name, uint32_t Flags,
 
   Symbol *S;
   bool WasInserted;
   std::tie(S, WasInserted) = insert(Name);
 
   if (WasInserted)
     replaceSymbol<UndefinedFunction>(S, Name, Flags, File, Sig);
   else if (auto *Lazy = dyn_cast<LazySymbol>(S))
-    cast<ArchiveFile>(Lazy->getFile())->addMember(&Lazy->getArchiveSymbol());
+    Lazy->fetch();
   else if (S->isDefined())
     checkFunctionType(S, File, Sig);
   return S;
 }
 
 Symbol *SymbolTable::addUndefinedData(StringRef Name, uint32_t Flags,
                                       InputFile *File) {
   DEBUG(dbgs() << "addUndefinedData: " << Name << "\n");
 
   Symbol *S;
   bool WasInserted;
   std::tie(S, WasInserted) = insert(Name);
 
   if (WasInserted)
     replaceSymbol<UndefinedData>(S, Name, Flags, File);
   else if (auto *Lazy = dyn_cast<LazySymbol>(S))
-    cast<ArchiveFile>(Lazy->getFile())->addMember(&Lazy->getArchiveSymbol());
+    Lazy->fetch();
   else if (S->isDefined())
     checkDataType(S, File);
   return S;
 }
 
 Symbol *SymbolTable::addUndefinedGlobal(StringRef Name, uint32_t Flags,
                                         InputFile *File,
                                         const WasmGlobalType *Type) {
   DEBUG(dbgs() << "addUndefinedGlobal: " << Name << "\n");
 
   Symbol *S;
   bool WasInserted;
   std::tie(S, WasInserted) = insert(Name);
 
   if (WasInserted)
     replaceSymbol<UndefinedGlobal>(S, Name, Flags, File, Type);
   else if (auto *Lazy = dyn_cast<LazySymbol>(S))
-    cast<ArchiveFile>(Lazy->getFile())->addMember(&Lazy->getArchiveSymbol());
+    Lazy->fetch();
   else if (S->isDefined())
     checkGlobalType(S, File, Type);
   return S;
 }
 
 void SymbolTable::addLazy(ArchiveFile *File, const Archive::Symbol *Sym) {
   DEBUG(dbgs() << "addLazy: " << Sym->getName() << "\n");
   StringRef Name = Sym->getName();

wasm/Symbols.h

 };
 
 class LazySymbol : public Symbol {
 public:
   LazySymbol(StringRef Name, InputFile *File, const Archive::Symbol &Sym)
       : Symbol(Name, LazyKind, 0, File), ArchiveSymbol(Sym) {}
 
   static bool classof(const Symbol *S) { return S->kind() == LazyKind; }
+  void fetch();
 
-  const Archive::Symbol &getArchiveSymbol() { return ArchiveSymbol; }
-
-protected:
+private:
   Archive::Symbol ArchiveSymbol;
 };
 
 // linker-generated symbols
 struct WasmSym {
   // __stack_pointer
   // Global that holds the address of the top of the explicit value stack in
   // linear memory.

wasm/Symbols.cpp

 }
 
 DefinedGlobal::DefinedGlobal(StringRef Name, uint32_t Flags, InputFile *File,
                              InputGlobal *Global)
     : GlobalSymbol(Name, DefinedGlobalKind, Flags, File,
                    Global ? &Global->getType() : nullptr),
       Global(Global) {}
 
+void LazySymbol::fetch() { cast<ArchiveFile>(File)->addMember(&ArchiveSymbol); }
+
 std::string lld::toString(const wasm::Symbol &Sym) {
   if (Config->Demangle)
     if (Optional<std::string> S = demangleItanium(Sym.getName()))
       return "`" + *S + "'";
   return Sym.getName();
 }
 
 std::string lld::toString(wasm::Symbol::Kind Kind) {