Index: lib/Support/Windows/Signals.inc
===================================================================
--- lib/Support/Windows/Signals.inc
+++ lib/Support/Windows/Signals.inc
@@ -151,6 +151,12 @@
 typedef BOOL (WINAPI *fpEnumerateLoadedModules)(HANDLE,PENUMLOADED_MODULES_CALLBACK64,PVOID);
 static fpEnumerateLoadedModules fEnumerateLoadedModules;
 
+typedef BOOL (WINAPI * fpMiniDumpWriteDump)(HANDLE,DWORD,HANDLE,MINIDUMP_TYPE,
+	CONST PMINIDUMP_EXCEPTION_INFORMATION,
+	CONST PMINIDUMP_USER_STREAM_INFORMATION,
+	CONST PMINIDUMP_CALLBACK_INFORMATION);
+static fpMiniDumpWriteDump fMiniDumpWriteDump;
+
 static bool load64BitDebugHelp(void) {
   HMODULE hLib = ::LoadLibraryW(L"Dbghelp.dll");
   if (hLib) {
@@ -170,8 +176,10 @@
     fSymInitialize = (fpSymInitialize)::GetProcAddress(hLib, "SymInitialize");
     fEnumerateLoadedModules = (fpEnumerateLoadedModules)
       ::GetProcAddress(hLib, "EnumerateLoadedModules64");
+    fMiniDumpWriteDump = (fpMiniDumpWriteDump)
+      ::GetProcAddress(hLib, "MiniDumpWriteDump");
   }
-  return fStackWalk64 && fSymInitialize && fSymSetOptions;
+  return fStackWalk64 && fSymInitialize && fSymSetOptions && fMiniDumpWriteDump;
 }
 
 using namespace llvm;
@@ -361,6 +369,93 @@
   }
 }
 
+static void WINAPI CreateMiniDump(llvm::raw_ostream &OS,
+                                  _EXCEPTION_POINTERS *pExceptionInfo) {
+  char buffer[_MAX_PATH];
+
+  DWORD length =
+      ::GetModuleFileName(::GetModuleHandle(0), buffer, sizeof(buffer));
+
+  // If GetModuleHandle fails, we would get the current process executable file
+  // name, which is fine.
+
+  if (length >= sizeof(buffer))
+    strcpy(buffer, "clang.exe");
+
+  char appName[_MAX_PATH];
+
+  _splitpath(buffer, NULL, NULL, appName, NULL);
+
+  DWORD tempPathLength = ::GetTempPath(sizeof(buffer), buffer);
+
+  // If GetTempPath fails, we would write minidump to the current directory.
+
+  if (tempPathLength >= sizeof(buffer))
+    tempPathLength = 0;
+
+  size_t maxPrefixLength = sizeof(buffer) - tempPathLength;
+
+  int prefixLength =
+      _snprintf(buffer + tempPathLength, maxPrefixLength, "%s", appName);
+
+  // If _snprintf fails, we would use 'minidump' as the prefix
+  // and write file to the current directory.
+
+  if (prefixLength <= 0 || prefixLength >= int(maxPrefixLength)) {
+    strcpy(buffer, "minidump");
+    prefixLength = strlen(buffer);
+  } else {
+    prefixLength += tempPathLength;
+  }
+
+  SYSTEMTIME systemTime;
+
+  ::GetSystemTime(&systemTime);
+
+  int maxSuffixLength = sizeof(buffer) - prefixLength;
+
+  int suffixLength = _snprintf(
+      buffer + prefixLength, maxSuffixLength,
+      ".%04d%02d%02d%02d%02d%02d%03d.dmp", systemTime.wYear, systemTime.wMonth,
+      systemTime.wDay, systemTime.wHour, systemTime.wMinute, systemTime.wSecond,
+      systemTime.wMilliseconds);
+
+  if (suffixLength <= 0 || suffixLength >= maxSuffixLength) {
+    _snprintf(buffer, sizeof(buffer),
+              "minidump.%04d%02d%02d%02d%02d%02d%03d.dmp", systemTime.wYear,
+              systemTime.wMonth, systemTime.wDay, systemTime.wHour,
+              systemTime.wMinute, systemTime.wSecond, systemTime.wMilliseconds);
+  }
+
+  HANDLE hFile = ::CreateFile(buffer, GENERIC_WRITE, FILE_SHARE_WRITE, 0,
+                              CREATE_NEW, FILE_ATTRIBUTE_NORMAL, 0);
+
+  bool writeMiniDumpSucceeded = false;
+  int errorCode = GetLastError();
+
+  if (hFile != INVALID_HANDLE_VALUE) {
+    _MINIDUMP_EXCEPTION_INFORMATION ExInfo;
+
+    ExInfo.ThreadId = ::GetCurrentThreadId();
+    ExInfo.ExceptionPointers = pExceptionInfo;
+    ExInfo.ClientPointers = NULL;
+
+    writeMiniDumpSucceeded = fMiniDumpWriteDump(
+        ::GetCurrentProcess(), ::GetCurrentProcessId(), hFile,
+        (MINIDUMP_TYPE)(MiniDumpNormal | MiniDumpWithDataSegs), &ExInfo, 0, 0);
+
+    errorCode = GetLastError();
+
+    ::CloseHandle(hFile);
+  }
+
+  if (writeMiniDumpSucceeded)
+    OS << "Minidump successfully saved: " << buffer << '\n';
+  else
+    OS << "Cannot create minidump file: " << buffer << " (error code "
+       << errorCode << ")\n";
+}
+
 namespace llvm {
 
 //===----------------------------------------------------------------------===//
@@ -587,9 +682,13 @@
 
   HANDLE hProcess = GetCurrentProcess();
   HANDLE hThread = GetCurrentThread();
-  PrintStackTraceForThread(llvm::errs(), hProcess, hThread, StackFrame,
+  llvm::raw_ostream &OS = llvm::errs();
+
+  PrintStackTraceForThread(OS, hProcess, hThread, StackFrame,
                            ep->ContextRecord);
 
+  CreateMiniDump(OS, ep);
+
   _exit(ep->ExceptionRecord->ExceptionCode);
 }