[bugpoint] Update runPasses to take ArrayRef instead of a pointer (NFC)

[fhahn]

Summary

This makes it slightly easier to pass extra arguments to runPasses
and simplifies the code slightly.

[hiraditya]

LGTM, makes it easier to read as well!

[dblaikie]

Looks good

llvm/tools/bugpoint/BugDriver.h

public:
   std::unique_ptr<Module>
   extractMappedBlocksFromModule(const std::vector<BasicBlock *> &BBs,
                                 Module *M);
 
   /// Carefully run the specified set of pass on the specified/ module,
   /// returning the transformed module on success, or a null pointer on failure.
   std::unique_ptr<Module> runPassesOn(Module *M,
                                       const std::vector<std::string> &Passes,
-                                      unsigned NumExtraArgs = 0,
-                                      const char *const *ExtraArgs = nullptr);
+                                      ArrayRef<std::string> ExtraArgs = {});
 
   /// runPasses - Run the specified passes on Program, outputting a bitcode
   /// file and writting the filename into OutputFile if successful.  If the
   /// optimizations fail for some reason (optimizer crashes), return true,
   /// otherwise return false.  If DeleteOutput is set to true, the bitcode is
   /// deleted on success, and the filename string is undefined.  This prints to
   /// outs() a single line message indicating whether compilation was successful
   /// or failed, unless Quiet is set.  ExtraArgs specifies additional arguments
   /// to pass to the child bugpoint instance.
   ///
   bool runPasses(Module &Program, const std::vector<std::string> &PassesToRun,
                  std::string &OutputFilename, bool DeleteOutput = false,
-                 bool Quiet = false, unsigned NumExtraArgs = 0,
-                 const char *const *ExtraArgs = nullptr) const;
+                 bool Quiet = false,
+                 ArrayRef<std::string> ExtraArgs = {}) const;
 
   /// runPasses - Just like the method above, but this just returns true or
   /// false indicating whether or not the optimizer crashed on the specified
   /// input (true = crashed).  Does not produce any output.
   ///
   bool runPasses(Module &M, const std::vector<std::string> &PassesToRun) const {
     std::string Filename;
     return runPasses(M, PassesToRun, Filename, true);

llvm/tools/bugpoint/ExtractFunction.cpp

if (OS.has_error()) {
     errs() << "Error writing list of blocks to not extract\n";
     EmitProgressBitcode(*M, "basicblockextractfail", true);
     OS.clear_error();
     return nullptr;
   }
 
   std::string uniqueFN = "--extract-blocks-file=";
   uniqueFN += Temp->TmpName;
-  const char *ExtraArg = uniqueFN.c_str();
 
   std::vector<std::string> PI;
   PI.push_back("extract-blocks");
-  std::unique_ptr<Module> Ret = runPassesOn(M, PI, 1, &ExtraArg);
+  std::unique_ptr<Module> Ret = runPassesOn(M, PI, {uniqueFN});
 
   if (!Ret) {
     outs() << "*** Basic Block extraction failed, please report a bug!\n";
     EmitProgressBitcode(*M, "basicblockextractfail", true);
   }
   return Ret;
 }

llvm/tools/bugpoint/OptimizerDriver.cpp

 /// otherwise return false.  If DeleteOutput is set to true, the bitcode is
 /// deleted on success, and the filename string is undefined.  This prints to
 /// outs() a single line message indicating whether compilation was successful
 /// or failed.
 ///
 bool BugDriver::runPasses(Module &Program,
                           const std::vector<std::string> &Passes,
                           std::string &OutputFilename, bool DeleteOutput,
-                          bool Quiet, unsigned NumExtraArgs,
-                          const char *const *ExtraArgs) const {
+                          bool Quiet, ArrayRef<std::string> ExtraArgs) const {
   // setup the output file name
   outs().flush();
   SmallString<128> UniqueFilename;
   std::error_code EC = sys::fs::createUniqueFile(
       OutputPrefix + "-output-%%%%%%%.bc", UniqueFilename);
   if (EC) {
     errs() << getToolName()
            << ": Error making unique filename: " << EC.message() << "\n";
for (std::vector<std::string>::const_iterator I = Passes.begin(),
                                                 E = Passes.end();
        I != E; ++I)
     pass_args.push_back(std::string("-") + (*I));
   for (std::vector<std::string>::const_iterator I = pass_args.begin(),
                                                 E = pass_args.end();
        I != E; ++I)
     Args.push_back(I->c_str());
   Args.push_back(Temp->TmpName.c_str());
-  for (unsigned i = 0; i < NumExtraArgs; ++i)
-    Args.push_back(*ExtraArgs);
+  Args.append(ExtraArgs.begin(), ExtraArgs.end());
 
   LLVM_DEBUG(errs() << "\nAbout to run:\t";
              for (unsigned i = 0, e = Args.size() - 1; i != e; ++i) errs()
              << " " << Args[i];
              errs() << "\n";);
 
   Optional<StringRef> Redirects[3] = {None, None, None};
   // Redirect stdout and stderr to nowhere if SilencePasses is given.
bool BugDriver::runPasses(Module &Program,
   }
 
   // Was the child successful?
   return result != 0;
 }
 
 std::unique_ptr<Module>
 BugDriver::runPassesOn(Module *M, const std::vector<std::string> &Passes,
-                       unsigned NumExtraArgs, const char *const *ExtraArgs) {
+                       ArrayRef<std::string> ExtraArgs) {
   std::string BitcodeResult;
   if (runPasses(*M, Passes, BitcodeResult, false /*delete*/, true /*quiet*/,
-                NumExtraArgs, ExtraArgs)) {
+                ExtraArgs)) {
     return nullptr;
   }
 
   std::unique_ptr<Module> Ret = parseInputFile(BitcodeResult, Context);
   if (!Ret) {
     errs() << getToolName() << ": Error reading bitcode file '" << BitcodeResult
            << "'!\n";
     exit(1);
   }
   sys::fs::remove(BitcodeResult);
   return Ret;
 }