From 4f45f5abe77525389e0a4d9885c5bf63e2f54bc8 Mon Sep 17 00:00:00 2001
From: Jonathan Yong <10walls@gmail.com>
Date: Fri, 31 Oct 2014 06:46:02 +0800
Subject: [PATCH 22/24] prevent modules from being unloaded before their dtors
 are called

---
 libstdc++-v3/config/os/mingw32-w64/os_defines.h |  5 +++++
 libstdc++-v3/config/os/newlib/os_defines.h      |  6 ++++++
 libstdc++-v3/libsupc++/atexit_thread.cc         | 20 ++++++++++++++++++++
 3 files changed, 31 insertions(+)

diff --git a/libstdc++-v3/config/os/mingw32-w64/os_defines.h b/libstdc++-v3/config/os/mingw32-w64/os_defines.h
index fd5ad9e..41d59be 100644
--- a/libstdc++-v3/config/os/mingw32-w64/os_defines.h
+++ b/libstdc++-v3/config/os/mingw32-w64/os_defines.h
@@ -81,4 +81,9 @@
 // See libstdc++/59807
 #define _GTHREAD_USE_MUTEX_INIT_FUNC 1
 
+// Enable use of GetModuleHandleEx (requires Windows XP/2003) in
+// __cxa_thread_atexit to prevent modules from being unloaded before
+// their dtors are called
+#define _GLIBCXX_THREAD_ATEXIT_WIN32 1
+
 #endif
diff --git a/libstdc++-v3/config/os/newlib/os_defines.h b/libstdc++-v3/config/os/newlib/os_defines.h
index 92748da..2e01d3b 100644
--- a/libstdc++-v3/config/os/newlib/os_defines.h
+++ b/libstdc++-v3/config/os/newlib/os_defines.h
@@ -47,6 +47,12 @@
 
 // See libstdc++/20806.
 #define _GLIBCXX_HAVE_DOS_BASED_FILESYSTEM 1
+
+// Enable use of GetModuleHandleEx (requires Windows XP/2003) in
+// __cxa_thread_atexit to prevent modules from being unloaded before
+// their dtors are called
+#define _GLIBCXX_THREAD_ATEXIT_WIN32 1
+
 #endif
 
 #endif
diff --git a/libstdc++-v3/libsupc++/atexit_thread.cc b/libstdc++-v3/libsupc++/atexit_thread.cc
index dff08e9..d7d84d2 100644
--- a/libstdc++-v3/libsupc++/atexit_thread.cc
+++ b/libstdc++-v3/libsupc++/atexit_thread.cc
@@ -25,6 +25,10 @@
 #include <cstdlib>
 #include <new>
 #include "bits/gthr.h"
+#ifdef _GLIBCXX_THREAD_ATEXIT_WIN32
+#define WIN32_LEAN_AND_MEAN
+#include <windows.h>
+#endif
 
 #if _GLIBCXX_HAVE___CXA_THREAD_ATEXIT_IMPL
 
@@ -47,6 +51,9 @@ namespace {
     void (*destructor)(void *);
     void *object;
     elt *next;
+#ifdef _GLIBCXX_THREAD_ATEXIT_WIN32
+    HMODULE dll;
+#endif
   };
 
   // Keep a per-thread list of cleanups in gthread_key storage.
@@ -62,6 +69,11 @@ namespace {
       {
 	elt *old_e = e;
 	e->destructor (e->object);
+#ifdef _GLIBCXX_THREAD_ATEXIT_WIN32
+	/* Decrement DLL count */
+	if (e->dll)
+	  FreeLibrary (e->dll);
+#endif
 	e = e->next;
 	delete (old_e);
       }
@@ -133,6 +145,14 @@ __cxxabiv1::__cxa_thread_atexit (void (*dtor)(void *), void *obj, void */*dso_ha
   new_elt->destructor = dtor;
   new_elt->object = obj;
   new_elt->next = first;
+#ifdef _GLIBCXX_THREAD_ATEXIT_WIN32
+  /* Store the DLL address for a later call to FreeLibrary in new_elt and
+     increment DLL load count.  This blocks the unloading of the DLL
+     before the thread-local dtors have been called.  This does NOT help
+     if FreeLibrary/dlclose is called in excess. */
+  GetModuleHandleExW (GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS,
+		      (LPCWSTR) dtor, &new_elt->dll);
+#endif
 
   if (__gthread_active_p ())
     __gthread_setspecific (key, new_elt);
-- 
2.1.1