Thoroughly rehack the dynamic linking mechanisms on Win32. The Win32

dynamic linker does not automatically search libraries when looking up
symbols with GetProcAddress.  Because of this we have to emulate it.  The
only detail is that there doesn't seem to be a way to enumerate the
libraries loaded, so we have a gross hack (tm).

This make the JIT functional on win32 under cygwin.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@13887 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Support/DynamicLinker.cpp

@@ -12,8 +12,7 @@
 // provides it.
 //
 // Possible future extensions include support for the HPUX shl_load()
-// interface, the Mac OS X NSLinkModule() interface, and the Windows
+// interface, and the Mac OS X NSLinkModule() interface.
-// LoadLibrary() interface.
 //
 // Note that we assume that if dlopen() is available, then dlsym() is too.
 //
@@ -23,18 +22,36 @@
 #include "Config/dlfcn.h"
 #include "Config/windows.h"
 #include <cassert>
+#include <vector>
 using namespace llvm;
 
-bool llvm::LinkDynamicObject (const char *filename, std::string *ErrorMessage) {
+#if defined(HAVE_WINDOWS_H)
-#if defined (HAVE_DLOPEN)
+// getLoadedLibs - Keep track of the shared objects that are loaded into the
-  if (dlopen (filename, RTLD_NOW | RTLD_GLOBAL) == 0) {
+// process address space, as the windows GetProcAddress function does not
-    if (ErrorMessage) *ErrorMessage = dlerror ();
+// automatically search an entire address space, it only searches a specific
-    return true;
+// object.
+static std::vector<HMODULE> &getLoadedLibHandles() {
+  static std::vector<HMODULE> *LoadedLibHandles = 0;
+  if (LoadedLibHandles == 0) {
+    LoadedLibHandles = new std::vector<HMODULE>();
+    if (HMODULE H = GetModuleHandle(NULL))                // JIT symbols
+      LoadedLibHandles->push_back(H);
+    if (HMODULE MH = GetModuleHandle("cygwin1.dll"))      // Cygwin symbols OR
+      LoadedLibHandles->push_back(MH);
+    else if (HMODULE MH = GetModuleHandle("msvcr80.dll")) // VC++ symbols
+      LoadedLibHandles->push_back(MH);
   }
+  return *LoadedLibHandles;
+}
+#endif
+
+bool llvm::LinkDynamicObject(const char *filename, std::string *ErrorMessage) {
+#if defined(HAVE_WINDOWS_H)
+  if (HMODULE Handle = LoadLibrary(filename)) {
+    // Allow GetProcAddress in this module
+    getLoadedLibHandles().push_back(Handle);
     return false;
-#elif defined(HAVE_WINDOWS_H)
+  }
-  if (LoadLibrary(filename))
-    return false;
   if (ErrorMessage) {
     char Buffer[100];
     // FIXME: This should use FormatMessage
@@ -42,23 +59,31 @@ bool llvm::LinkDynamicObject (const char *filename, std::string *ErrorMessage) {
     *ErrorMessage = Buffer;
   }
   return true;
+#elif defined (HAVE_DLOPEN)
+  if (dlopen (filename, RTLD_NOW | RTLD_GLOBAL) == 0) {
+    if (ErrorMessage) *ErrorMessage = dlerror ();
+    return true;
+  }
+  return false;
 #else
   assert (0 && "Dynamic object linking not implemented for this platform");
 #endif
 }
 
 void *llvm::GetAddressOfSymbol(const char *symbolName) {
-#if defined (HAVE_DLOPEN)
+#if defined(HAVE_WINDOWS_H)
+  std::vector<HMODULE> &LH = getLoadedLibHandles();
+  for (unsigned i = 0, e = LH.size(); i != e; ++i)
+    if (void *Val = (void*)GetProcAddress(LH[i], symbolName))
+      return Val;
+  return 0;
+#elif defined(HAVE_DLOPEN)
 #  ifdef RTLD_DEFAULT
     return dlsym (RTLD_DEFAULT, symbolName);
 #  else
     static void* CurHandle = dlopen(0, RTLD_LAZY);
     return dlsym(CurHandle, symbolName);
 #  endif
-#elif defined(HAVE_WINDOWS_H)
-  static HMODULE ModHandle = NULL;
-  if (ModHandle == 0) ModHandle = GetModuleHandle(NULL);
-  return (void*)GetProcAddress(ModHandle, symbolName);
 #else
   assert (0 && "Dynamic symbol lookup not implemented for this platform");
 #endif