vendor/llvm/llvm-trunk-r241361

1 files changed, 20 insertions, 10 deletions

diff --git a/lib/Support/Windows/DynamicLibrary.inc b/lib/Support/Windows/DynamicLibrary.inc
index 79d5f79afa97..d38f19749118 100644
--- a/lib/Support/Windows/DynamicLibrary.inc
+++ b/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 @@ using namespace sys;
 //===          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 @@ DynamicLibrary DynamicLibrary::getPermanentLibrary(const char *filename,
     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);