Windows: Add support for unicode command lines

Summary:
The MSVCRT deliberately sends main() code-page specific characters.
This isn't too useful to LLVM as we end up converting the arguments to
UTF-16 and subsequently attempt to use the result as, for example, a
file name.  Instead, we need to have the ability to access the Unicode
command line and transform it to UTF-8.

This has the distinct advantage over using the MSVC-specific wmain()
function as our entry point because:
 - It doesn't work on cygwin.
 - It only work on MinGW with caveats and only then on certain versions.
 - We get to keep our entry point as main(). :)

N.B.  This patch includes fixes to other parts of lib/Support/Windows
s.t. we would be able to take advantage of getting the Unicode paths.
E.G.  clang spawning clang -cc1 would want to give it Unicode arguments.

Reviewers: aaron.ballman, Bigcheese, rnk, ruiu

Reviewed By: rnk

CC: llvm-commits, ygao

Differential Revision: http://llvm-reviews.chandlerc.com/D1834

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@192069 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 8 insertions, 1 deletions

diff --git a/lib/Support/Windows/DynamicLibrary.inc b/lib/Support/Windows/DynamicLibrary.inc
index 2edaf74fa5..5a7b21920a 100644
--- a/lib/Support/Windows/DynamicLibrary.inc
+++ b/lib/Support/Windows/DynamicLibrary.inc
@@ -83,8 +83,15 @@ DynamicLibrary DynamicLibrary::getPermanentLibrary(const char *filename,
     // This is mostly to ensure that the return value still shows up as "valid".
     return DynamicLibrary(&OpenedHandles);
   }
+
+  SmallVector<wchar_t, MAX_PATH> filenameUnicode;
+  if (error_code ec = windows::UTF8ToUTF16(filename, filenameUnicode)) {
+    SetLastError(ec.value());
+    MakeErrMsg(errMsg, std::string(filename) + ": Can't convert to UTF-16: ");
+    return DynamicLibrary();
+  }
   
-  HMODULE a_handle = LoadLibrary(filename);
+  HMODULE a_handle = LoadLibraryW(filenameUnicode.data());
 
   if (a_handle == 0) {
     MakeErrMsg(errMsg, std::string(filename) + ": Can't open : ");