[LLDB] [Driver] Use llvm::InitLLVM to do unicode argument conversion on Windows

[mstorsjo]

Summary

This avoids the currently MSVC specific codepath of using the wchar entry point and converting that to utf8.

In the main lldb driver, we had this MSVC specific codepath, but in other potentially important entry points (like lldb-server), there's none at all. So if this is fine, we should probably add the same InitLLVM call to other lldb entry points as well.

[amccarth]

Cool. I didn't know about InitLLVM. That makes things much cleaner.

Though I do recall recently seeing another complaint about argv[0] not being preserved as typed but being replaced by an absolute path. That will definitely happen now on Windows. Is that a problem?

[mstorsjo]

In D68770#1704663, @amccarth wrote:

Cool. I didn't know about InitLLVM. That makes things much cleaner.

Though I do recall recently seeing another complaint about argv[0] not being preserved as typed but being replaced by an absolute path. That will definitely happen now on Windows. Is that a problem?

I remember seeing such behaviour elsewhere (clang) as well. I don't think that InitLLVM does any such rewrite of argv[0] though, so this patch should pretty much be a plain refactoring.

[amccarth]

On Windows, it _does_ rewrite argv[0], but it looks like it tries to not change whether it was relative/absolute, so I think this is fine.

Thanks for the clean-up!

lldb/tools/driver/Driver.cpp

 #include "lldb/API/SBFile.h"
 #include "lldb/API/SBHostOS.h"
 #include "lldb/API/SBLanguageRuntime.h"
 #include "lldb/API/SBReproducer.h"
 #include "lldb/API/SBStream.h"
 #include "lldb/API/SBStringList.h"
 
 #include "llvm/ADT/StringRef.h"
-#include "llvm/Support/ConvertUTF.h"
 #include "llvm/Support/Format.h"
+#include "llvm/Support/InitLLVM.h"
 #include "llvm/Support/Path.h"
 #include "llvm/Support/PrettyStackTrace.h"
 #include "llvm/Support/Process.h"
 #include "llvm/Support/Signals.h"
 #include "llvm/Support/WithColor.h"
 #include "llvm/Support/raw_ostream.h"
 
 #include <algorithm>
if (capture_path) {
         return 1;
       }
     }
   }
 
   return llvm::None;
 }
 
-int
-#ifdef _MSC_VER
-wmain(int argc, wchar_t const *wargv[])
-#else
-main(int argc, char const *argv[])
-#endif
+int main(int argc, char const *argv[])
 {
-#ifdef _MSC_VER
-  // Convert wide arguments to UTF-8
-  std::vector<std::string> argvStrings(argc);
-  std::vector<const char *> argvPointers(argc);
-  for (int i = 0; i != argc; ++i) {
-    llvm::convertWideToUTF8(wargv[i], argvStrings[i]);
-    argvPointers[i] = argvStrings[i].c_str();
-  }
-  const char **argv = argvPointers.data();
-#endif
+  llvm::InitLLVM IL(argc, argv);
 
   // Print stack trace on crash.
   llvm::StringRef ToolName = llvm::sys::path::filename(argv[0]);
   llvm::sys::PrintStackTraceOnErrorSignal(ToolName);
   llvm::PrettyStackTraceProgram X(argc, argv);
 
   // Parse arguments.
   LLDBOptTable T;