Consistently bail out if we fail to parse command line args

[ruiu]

I think the point of the existing code is to find as many command line argument errors as possible in one execution of the linker. I wonder what you are trying to fix with this patch.

[sbc100]

I just noticed that the two linkers were inconsistent.

With wasm I was seening "unknown arg XXX" and then also always the "no input file". The ELF linker seems to sneekly get around this by only shown "no input files" in no other errors have been seen. But I don't think we should even be calling createFiles in the case that there is an incorrect command line flag.

ELF/Driver.cpp

if (K2 == Arg->getValue())
       return false;
   }
   return Default;
 }
 
 void LinkerDriver::main(ArrayRef<const char *> ArgsArr) {
   ELFOptTable Parser;
   opt::InputArgList Args = Parser.parse(ArgsArr.slice(1));
+  if (errorCount())
+    return;
 
   // Interpret this flag early because error() depends on them.
   errorHandler().ErrorLimit = args::getInteger(Args, OPT_error_limit, 20);
 
   // Handle -help
   if (Args.hasArg(OPT_help)) {
     printHelp();
     return;
case OPT_pop_state:
         break;
       }
       std::tie(Config->AsNeeded, Config->Static, InWholeArchive) = Stack.back();
       Stack.pop_back();
       break;
     }
   }
 
-  if (Files.empty() && errorCount() == 0)
+  if (Files.empty())
     error("no input files");
 }
 
 // If -m <machine_type> was not given, infer it from object files.
 void LinkerDriver::inferMachineType() {
   if (Config->EKind != ELFNoneKind)
     return;
 

wasm/Driver.cpp

static Symbol *addUndefined(StringRef Name) {
   S->IsUsedInRegularObj = true;
 
   return S;
 }
 
 void LinkerDriver::link(ArrayRef<const char *> ArgsArr) {
   WasmOptTable Parser;
   opt::InputArgList Args = Parser.parse(ArgsArr.slice(1));
+  if (errorCount())
+    return;
 
   // Handle --help
   if (Args.hasArg(OPT_help)) {
     Parser.PrintHelp(outs(), ArgsArr[0], "LLVM Linker", false);
     return;
   }
 
   // Handle --version
if (!Config->Entry.empty())
       EntrySym = addUndefined(Config->Entry);
 
     // Handle the `--undefined <sym>` options.
     for (auto *Arg : Args.filtered(OPT_undefined))
       addUndefined(Arg->getValue());
   }
 
   createFiles(Args);
-  if (errorCount())
-    return;
 
   // Add all files to the symbol table. This will add almost all
   // symbols that we need to the symbol table.
   for (InputFile *F : Files)
     Symtab->addFile(F);
   if (errorCount())
     return;