Index: cmake/config-ix.cmake
===================================================================
--- cmake/config-ix.cmake
+++ cmake/config-ix.cmake
@@ -397,12 +397,10 @@
 endif ()
 
 if( MINGW )
-  set(HAVE_LIBIMAGEHLP 1)
   set(HAVE_LIBPSAPI 1)
   set(HAVE_LIBSHELL32 1)
   # TODO: Check existence of libraries.
   #   include(CheckLibraryExists)
-  #   CHECK_LIBRARY_EXISTS(imagehlp ??? . HAVE_LIBIMAGEHLP)
 endif( MINGW )
 
 if (NOT HAVE_STRTOLL)
Index: configure
===================================================================
--- configure
+++ configure
@@ -8658,87 +8658,6 @@
 
 if test "$llvm_cv_os_type" = "MingW" ; then
 
-{ echo "$as_me:$LINENO: checking for main in -limagehlp" >&5
-echo $ECHO_N "checking for main in -limagehlp... $ECHO_C" >&6; }
-if test "${ac_cv_lib_imagehlp_main+set}" = set; then
-  echo $ECHO_N "(cached) $ECHO_C" >&6
-else
-  ac_check_lib_save_LIBS=$LIBS
-LIBS="-limagehlp  $LIBS"
-cat >conftest.$ac_ext <<_ACEOF
-/* confdefs.h.  */
-_ACEOF
-cat confdefs.h >>conftest.$ac_ext
-cat >>conftest.$ac_ext <<_ACEOF
-/* end confdefs.h.  */
-
-
-int
-main ()
-{
-return main ();
-  ;
-  return 0;
-}
-_ACEOF
-rm -f conftest.$ac_objext conftest$ac_exeext
-if { (ac_try="$ac_link"
-case "(($ac_try" in
-  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
-  *) ac_try_echo=$ac_try;;
-esac
-eval "echo \"\$as_me:$LINENO: $ac_try_echo\"") >&5
-  (eval "$ac_link") 2>conftest.er1
-  ac_status=$?
-  grep -v '^ *+' conftest.er1 >conftest.err
-  rm -f conftest.er1
-  cat conftest.err >&5
-  echo "$as_me:$LINENO: \$? = $ac_status" >&5
-  (exit $ac_status); } &&
-	 { ac_try='test -z "$ac_c_werror_flag" || test ! -s conftest.err'
-  { (case "(($ac_try" in
-  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
-  *) ac_try_echo=$ac_try;;
-esac
-eval "echo \"\$as_me:$LINENO: $ac_try_echo\"") >&5
-  (eval "$ac_try") 2>&5
-  ac_status=$?
-  echo "$as_me:$LINENO: \$? = $ac_status" >&5
-  (exit $ac_status); }; } &&
-	 { ac_try='test -s conftest$ac_exeext'
-  { (case "(($ac_try" in
-  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
-  *) ac_try_echo=$ac_try;;
-esac
-eval "echo \"\$as_me:$LINENO: $ac_try_echo\"") >&5
-  (eval "$ac_try") 2>&5
-  ac_status=$?
-  echo "$as_me:$LINENO: \$? = $ac_status" >&5
-  (exit $ac_status); }; }; then
-  ac_cv_lib_imagehlp_main=yes
-else
-  echo "$as_me: failed program was:" >&5
-sed 's/^/| /' conftest.$ac_ext >&5
-
-	ac_cv_lib_imagehlp_main=no
-fi
-
-rm -f core conftest.err conftest.$ac_objext \
-      conftest$ac_exeext conftest.$ac_ext
-LIBS=$ac_check_lib_save_LIBS
-fi
-{ echo "$as_me:$LINENO: result: $ac_cv_lib_imagehlp_main" >&5
-echo "${ECHO_T}$ac_cv_lib_imagehlp_main" >&6; }
-if test $ac_cv_lib_imagehlp_main = yes; then
-  cat >>confdefs.h <<_ACEOF
-#define HAVE_LIBIMAGEHLP 1
-_ACEOF
-
-  LIBS="-limagehlp $LIBS"
-
-fi
-
-
 { echo "$as_me:$LINENO: checking for main in -lole32" >&5
 echo $ECHO_N "checking for main in -lole32... $ECHO_C" >&6; }
 if test "${ac_cv_lib_ole32_main+set}" = set; then
Index: include/llvm/Config/config.h.cmake
===================================================================
--- include/llvm/Config/config.h.cmake
+++ include/llvm/Config/config.h.cmake
@@ -125,9 +125,6 @@
 /* Define if you have the libdl library or equivalent. */
 #cmakedefine HAVE_LIBDL ${HAVE_LIBDL}
 
-/* Define to 1 if you have the `imagehlp' library (-limagehlp). */
-#cmakedefine HAVE_LIBIMAGEHLP ${HAVE_LIBIMAGEHLP}
-
 /* Define to 1 if you have the `m' library (-lm). */
 #undef HAVE_LIBM
 
Index: include/llvm/Config/config.h.in
===================================================================
--- include/llvm/Config/config.h.in
+++ include/llvm/Config/config.h.in
@@ -137,9 +137,6 @@
 /* Define if libedit is available on this platform. */
 #undef HAVE_LIBEDIT
 
-/* Define to 1 if you have the `imagehlp' library (-limagehlp). */
-#undef HAVE_LIBIMAGEHLP
-
 /* Define to 1 if you have the `m' library (-lm). */
 #undef HAVE_LIBM
 
Index: lib/Support/CMakeLists.txt
===================================================================
--- lib/Support/CMakeLists.txt
+++ lib/Support/CMakeLists.txt
@@ -1,7 +1,7 @@
 set(system_libs)
 if( NOT MSVC )
   if( MINGW )
-    set(system_libs ${system_libs} imagehlp psapi shell32 ole32)
+    set(system_libs ${system_libs} psapi shell32 ole32)
   elseif( CMAKE_HOST_UNIX )
     if( HAVE_LIBRT )
       set(system_libs ${system_libs} rt)
Index: lib/Support/Windows/DynamicLibrary.inc
===================================================================
--- lib/Support/Windows/DynamicLibrary.inc
+++ lib/Support/Windows/DynamicLibrary.inc
@@ -23,14 +23,6 @@
  #include <ntverp.h>
 #endif
 
-#ifdef __MINGW32__
- #if (HAVE_LIBIMAGEHLP != 1)
-  #error "libimagehlp.a should be present"
- #endif
-#else
- #pragma comment(lib, "dbghelp.lib")
-#endif
-
 namespace llvm {
 using namespace sys;
 
@@ -39,10 +31,21 @@
 //===          and must not be UNIX code.
 //===----------------------------------------------------------------------===//
 
+typedef BOOL (WINAPI *fpEnumerateLoadedModules)(HANDLE,PENUMLOADED_MODULES_CALLBACK64,PVOID);
+static fpEnumerateLoadedModules fEnumerateLoadedModules;
 static DenseSet<HMODULE> *OpenedHandles;
 
+static bool loadDebugHelp(void) {
+  HMODULE hLib = ::LoadLibraryW(L"Dbghelp.dll");
+  if (hLib) {
+    fEnumerateLoadedModules = (fpEnumerateLoadedModules)
+      ::GetProcAddress(hLib, "EnumerateLoadedModules64");
+  }
+  return fEnumerateLoadedModules != 0;
+}
+
 static BOOL CALLBACK
-ELM_Callback(WIN32_ELMCB_PCSTR ModuleName, ULONG_PTR ModuleBase,
+ELM_Callback(WIN32_ELMCB_PCSTR ModuleName, DWORD64 ModuleBase,
              ULONG ModuleSize, PVOID UserContext) {
   OpenedHandles->insert((HMODULE)ModuleBase);
   return TRUE;
@@ -57,7 +60,14 @@
     if (OpenedHandles == 0)
       OpenedHandles = new DenseSet<HMODULE>();
 
-    EnumerateLoadedModules(GetCurrentProcess(), ELM_Callback, 0);
+    if (!fEnumerateLoadedModules) {
+      if (!loadDebugHelp()) {
+        assert(false && "These APIs should always be available");
+        return DynamicLibrary();
+      }
+    }
+
+    fEnumerateLoadedModules(GetCurrentProcess(), ELM_Callback, 0);
     // Dummy library that represents "search all handles".
     // This is mostly to ensure that the return value still shows up as "valid".
     return DynamicLibrary(&OpenedHandles);
Index: lib/Support/Windows/Signals.inc
===================================================================
--- lib/Support/Windows/Signals.inc
+++ lib/Support/Windows/Signals.inc
@@ -31,10 +31,9 @@
 
 #ifdef _MSC_VER
  #pragma comment(lib, "psapi.lib")
- #pragma comment(lib, "dbghelp.lib")
 #elif __MINGW32__
- #if ((HAVE_LIBIMAGEHLP != 1) || (HAVE_LIBPSAPI != 1))
-  #error "libimagehlp.a & libpsapi.a should be present"
+ #if (HAVE_LIBPSAPI != 1)
+  #error "libpsapi.a should be present"
  #endif
  // The version of g++ that comes with MinGW does *not* properly understand
  // the ll format specifier for printf. However, MinGW passes the format
@@ -103,6 +102,8 @@
    DWORD64     Reserved[3];
    KDHELP64    KdHelp;
  } STACKFRAME64, *LPSTACKFRAME64;
+ #endif // !defined(__MINGW64_VERSION_MAJOR)
+#endif // __MINGW32__
 
 typedef BOOL (__stdcall *PREAD_PROCESS_MEMORY_ROUTINE64)(HANDLE hProcess,
                       DWORD64 qwBaseAddress, PVOID lpBuffer, DWORD nSize,
@@ -122,40 +123,46 @@
                       PFUNCTION_TABLE_ACCESS_ROUTINE64,
                       PGET_MODULE_BASE_ROUTINE64,
                       PTRANSLATE_ADDRESS_ROUTINE64);
-static fpStackWalk64 StackWalk64;
+static fpStackWalk64 fStackWalk64;
 
 typedef DWORD64 (WINAPI *fpSymGetModuleBase64)(HANDLE, DWORD64);
-static fpSymGetModuleBase64 SymGetModuleBase64;
+static fpSymGetModuleBase64 fSymGetModuleBase64;
 
 typedef BOOL (WINAPI *fpSymGetSymFromAddr64)(HANDLE, DWORD64,
                       PDWORD64, PIMAGEHLP_SYMBOL64);
-static fpSymGetSymFromAddr64 SymGetSymFromAddr64;
+static fpSymGetSymFromAddr64 fSymGetSymFromAddr64;
 
 typedef BOOL (WINAPI *fpSymGetLineFromAddr64)(HANDLE, DWORD64,
                       PDWORD, PIMAGEHLP_LINE64);
-static fpSymGetLineFromAddr64 SymGetLineFromAddr64;
+static fpSymGetLineFromAddr64 fSymGetLineFromAddr64;
 
 typedef PVOID (WINAPI *fpSymFunctionTableAccess64)(HANDLE, DWORD64);
-static fpSymFunctionTableAccess64 SymFunctionTableAccess64;
+static fpSymFunctionTableAccess64 fSymFunctionTableAccess64;
+
+typedef DWORD (WINAPI *fpSymSetOptions)(DWORD);
+static fpSymSetOptions fSymSetOptions;
+
+typedef BOOL (WINAPI *fpSymInitialize)(HANDLE, PCSTR, BOOL);
+static fpSymInitialize fSymInitialize;
 
 static bool load64BitDebugHelp(void) {
   HMODULE hLib = ::LoadLibraryW(L"Dbghelp.dll");
   if (hLib) {
-    StackWalk64 = (fpStackWalk64)
+    fStackWalk64 = (fpStackWalk64)
                       ::GetProcAddress(hLib, "StackWalk64");
-    SymGetModuleBase64 = (fpSymGetModuleBase64)
+    fSymGetModuleBase64 = (fpSymGetModuleBase64)
                       ::GetProcAddress(hLib, "SymGetModuleBase64");
-    SymGetSymFromAddr64 = (fpSymGetSymFromAddr64)
+    fSymGetSymFromAddr64 = (fpSymGetSymFromAddr64)
                       ::GetProcAddress(hLib, "SymGetSymFromAddr64");
-    SymGetLineFromAddr64 = (fpSymGetLineFromAddr64)
+    fSymGetLineFromAddr64 = (fpSymGetLineFromAddr64)
                       ::GetProcAddress(hLib, "SymGetLineFromAddr64");
-    SymFunctionTableAccess64 = (fpSymFunctionTableAccess64)
+    fSymFunctionTableAccess64 = (fpSymFunctionTableAccess64)
                      ::GetProcAddress(hLib, "SymFunctionTableAccess64");
+    fSymSetOptions = (fpSymSetOptions)::GetProcAddress(hLib, "SymSetOptions");
+    fSymInitialize = (fpSymInitialize)::GetProcAddress(hLib, "SymInitialize");
   }
-  return StackWalk64 != NULL;
+  return fStackWalk64 && fSymInitialize && fSymSetOptions;
 }
- #endif // !defined(__MINGW64_VERSION_MAJOR)
-#endif // __MINGW32__
 
 // Forward declare.
 static LONG WINAPI LLVMUnhandledExceptionFilter(LPEXCEPTION_POINTERS ep);
@@ -187,12 +194,12 @@
 #endif
 
   // Initialize the symbol handler.
-  SymSetOptions(SYMOPT_DEFERRED_LOADS | SYMOPT_LOAD_LINES);
-  SymInitialize(hProcess, NULL, TRUE);
+  fSymSetOptions(SYMOPT_DEFERRED_LOADS | SYMOPT_LOAD_LINES);
+  fSymInitialize(hProcess, NULL, TRUE);
 
   while (true) {
-    if (!StackWalk64(machineType, hProcess, hThread, &StackFrame, Context, NULL,
-                     SymFunctionTableAccess64, SymGetModuleBase64, NULL)) {
+    if (!fStackWalk64(machineType, hProcess, hThread, &StackFrame, Context, 0,
+                      fSymFunctionTableAccess64, fSymGetModuleBase64, 0)) {
       break;
     }
 
@@ -221,7 +228,7 @@
             static_cast<DWORD>(StackFrame.Params[3]));
 #endif
     // Verify the PC belongs to a module in this process.
-    if (!SymGetModuleBase64(hProcess, PC)) {
+    if (!fSymGetModuleBase64(hProcess, PC)) {
       OS << " <unknown module>\n";
       continue;
     }
@@ -234,7 +241,7 @@
     symbol->MaxNameLength = 512 - sizeof(IMAGEHLP_SYMBOL64);
 
     DWORD64 dwDisp;
-    if (!SymGetSymFromAddr64(hProcess, PC, &dwDisp, symbol)) {
+    if (!fSymGetSymFromAddr64(hProcess, PC, &dwDisp, symbol)) {
       OS << '\n';
       continue;
     }
@@ -250,7 +257,7 @@
     IMAGEHLP_LINE64 line = {};
     DWORD dwLineDisp;
     line.SizeOfStruct = sizeof(line);
-    if (SymGetLineFromAddr64(hProcess, PC, &dwLineDisp, &line)) {
+    if (fSymGetLineFromAddr64(hProcess, PC, &dwLineDisp, &line)) {
       OS << format(", %s, line %lu", line.FileName, line.LineNumber);
       if (dwLineDisp > 0)
         OS << format(" + 0x%lX byte(s)", dwLineDisp);
@@ -301,17 +308,13 @@
 }
 
 static void RegisterHandler() {
-#if __MINGW32__ && !defined(__MINGW64_VERSION_MAJOR)
-  // On MinGW.org, we need to load up the symbols explicitly, because the
-  // Win32 framework they include does not have support for the 64-bit
-  // versions of the APIs we need.  If we cannot load up the APIs (which
-  // would be unexpected as they should exist on every version of Windows
-  // we support), we will bail out since there would be nothing to report.
+  // If we cannot load up the APIs (which would be unexpected as they should
+  // exist on every version of Windows we support), we will bail out since
+  // there would be nothing to report.
   if (!load64BitDebugHelp()) {
     assert(false && "These APIs should always be available");
     return;
   }
-#endif
 
   if (RegisteredUnhandledExceptionFilter) {
     EnterCriticalSection(&CriticalSection);
Index: tools/llvm-symbolizer/LLVMSymbolize.cpp
===================================================================
--- tools/llvm-symbolizer/LLVMSymbolize.cpp
+++ tools/llvm-symbolizer/LLVMSymbolize.cpp
@@ -33,6 +33,7 @@
 #if defined(_MSC_VER)
 #include <Windows.h>
 #include <DbgHelp.h>
+#pragma comment(lib, "dbghelp.lib")
 #endif
 
 namespace llvm {