Driver: Use the canonical command line arguments.

[majnemer]

Summary

Use the arguments given to the OS at process creation-time instead of
the arguments passed into main() by the C runtime environment. The ones
that main() received may not be suitable (e.g. not Unicode).

Depends on D1834

[majnemer]

• Updated for LLVM changes.

[majnemer]

Closed by commit rL192091 (authored by @majnemer).

[ruiu]

cfe/trunk/tools/driver/driver.cpp

298

Naming convention in LLD is slightly different from LLVM. Local variables should start with lowercase and spelled as camel case.

[ruiu]

Ah, sorry, I thought that I was reviewing a LLD patch. This is for Clang. Please ignore the above comment.

cfe/trunk/tools/driver/driver.cpp

 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/Host.h"
 #include "llvm/Support/ManagedStatic.h"
 #include "llvm/Support/MemoryBuffer.h"
 #include "llvm/Support/Path.h"
 #include "llvm/Support/PrettyStackTrace.h"
+#include "llvm/Support/Process.h"
 #include "llvm/Support/Program.h"
 #include "llvm/Support/Regex.h"
 #include "llvm/Support/Signals.h"
 #include "llvm/Support/TargetRegistry.h"
 #include "llvm/Support/TargetSelect.h"
 #include "llvm/Support/Timer.h"
 #include "llvm/Support/raw_ostream.h"
 #include "llvm/Support/system_error.h"
private:
     std::set<std::string> &Storage;
   };
 }
 
 int main(int argc_, const char **argv_) {
   llvm::sys::PrintStackTraceOnErrorSignal();
   llvm::PrettyStackTraceProgram X(argc_, argv_);
 
+  SmallVector<const char *, 256> argv;
+  llvm::SpecificBumpPtrAllocator<char> ArgAllocator;
+  llvm::error_code EC = llvm::sys::Process::GetArgumentVector(
+      argv, llvm::ArrayRef<const char *>(argv_, argc_), ArgAllocator);
+  if (EC) {
+    llvm::errs() << "error: couldn't get arguments: " << EC.message() << '\n';
+    return 1;
+  }
+
   std::set<std::string> SavedStrings;
-  SmallVector<const char*, 256> argv(argv_, argv_ + argc_);
   StringSetSaver Saver(SavedStrings);
   llvm::cl::ExpandResponseFiles(Saver, llvm::cl::TokenizeGNUCommandLine, argv);
 
   // Handle -cc1 integrated tools.
   if (argv.size() > 1 && StringRef(argv[1]).startswith("-cc1")) {
     StringRef Tool = argv[1] + 4;
 
     if (Tool == "")