Add Windows error code and tidy formatting for system errors.

Differential Revision: http://reviews.llvm.org/D14892

llvm-svn: 253888

1 files changed, 8 insertions, 4 deletions

diff --git a/llvm/lib/Support/Windows/WindowsSupport.h b/llvm/lib/Support/Windows/WindowsSupport.h
index f12d2e43014..34d961b148d 100644
--- a/llvm/lib/Support/Windows/WindowsSupport.h
+++ b/llvm/lib/Support/Windows/WindowsSupport.h
@@ -32,6 +32,7 @@
 #define WIN32_LEAN_AND_MEAN
 
 #include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/StringExtras.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/ADT/Twine.h"
 #include "llvm/Config/config.h" // Get build system configuration settings
@@ -47,13 +48,16 @@ inline bool MakeErrMsg(std::string* ErrMsg, const std::string& prefix) {
   if (!ErrMsg)
     return true;
   char *buffer = NULL;
+  DWORD LastError = GetLastError();
   DWORD R = FormatMessage(FORMAT_MESSAGE_ALLOCATE_BUFFER |
-                          FORMAT_MESSAGE_FROM_SYSTEM,
-                          NULL, GetLastError(), 0, (LPSTR)&buffer, 1, NULL);
+                          FORMAT_MESSAGE_FROM_SYSTEM |
+                          FORMAT_MESSAGE_MAX_WIDTH_MASK,
+                          NULL, LastError, 0, (LPSTR)&buffer, 1, NULL);
   if (R)
-    *ErrMsg = prefix + buffer;
+    *ErrMsg = prefix + ": " + buffer;
   else
-    *ErrMsg = prefix + "Unknown error";
+    *ErrMsg = prefix + ": Unknown error";
+  *ErrMsg += " (0x" + llvm::utohexstr(LastError) + ")";
 
   LocalFree(buffer);
   return R != 0;