Revert 113748 - Provide windows notifictaion of thread termination

base/win/dllmain.cc

-// Copyright (c) 2011 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-// Windows doesn't support pthread_key_create's destr_function, and in fact
-// it's a bit tricky to get code to run when a thread exits.  This is
-// cargo-cult magic from http://www.codeproject.com/threads/tls.asp.
-// We are trying to be compatible with both a LoadLibrary style invocation, as
-// well as static linking. This code only needs to be included if we use
-// LoadLibrary, but it hooks into the "standard" set of TLS callbacks that are
-// provided for static linking.
-
-// This code is deliberately written to match the style of calls seen in
-// base/threading/thread_local_storage_win.cc.  Please keep the two in sync if
-// coding conventions are changed.
-
-// WARNING: Do *NOT* try to include this in the construction of the base
-// library, even though it potentially drives code in
-// base/threading/thread_local_storage_win.cc.  If you do, some users will end
-// up getting duplicate definition of DllMain() in some of their later links.
-
-// Force a reference to _tls_used to make the linker create the TLS directory
-// if it's not already there (that is, even if __declspec(thread) is not used).
-// To make sure we really traverse the whole list, we put down two elements, and
-// then check that we called both functions when we scanned the list.
-// Force a reference to p_thread_callback_dllmain_first_entry and
-// p_thread_callback_dllmain_first_entry to prevent whole program optimization
-// from discarding the variables.
-
-#include <windows.h>
-
-#include "base/logging.h"
-
-// Indicate if another service is scanning the callbacks.  When this becomes
-// set to true, then DllMain() will stop supporting the callback service. This
-// value is set to true the first time any of our callbacks are called, as that
-// shows that some other service is handling callbacks.
-static bool linker_notifications_are_active = false;
-
-// This will be our mostly no-op callback that we'll list (twice).  We won't
-// deliberately call it, and if it is called, that means we don't need to do any
-// of the callbacks anymore.  We expect such a call to arrive via a
-// THREAD_ATTACH message, long before we'd have to perform our THREAD_DETACH
-// callbacks.
-static void NTAPI on_callback(PVOID h, DWORD reason, PVOID reserved);
-
-#ifdef _WIN64
-
-#pragma comment(linker, "/INCLUDE:_tls_used")
-#pragma comment(linker, "/INCLUDE:p_thread_callback_dllmain_first_entry")
-#pragma comment(linker, "/INCLUDE:p_thread_callback_dllmain_later_entry")
-
-#else  // _WIN64
-
-#pragma comment(linker, "/INCLUDE:__tls_used")
-#pragma comment(linker, "/INCLUDE:_p_thread_callback_dllmain_first_entry")
-#pragma comment(linker, "/INCLUDE:_p_thread_callback_dllmain_later_entry")
-
-#endif  // _WIN64
-
-// extern "C" suppresses C++ name mangling so we know the symbol names for the
-// linker /INCLUDE:symbol pragmas above.
-extern "C" {
-#ifdef _WIN64
-
-// .CRT section is merged with .rdata on x64 so it must be constant data.
-#pragma data_seg(push, old_seg)
-// Use earliest possible name in the .CRT$XL? list of segments.
-#pragma const_seg(".CRT$XLA")
-// When defining a const variable, it must have external linkage to be sure the
-// linker doesn't discard it.
-extern const PIMAGE_TLS_CALLBACK p_thread_callback_dllmain_first_entry;
-const PIMAGE_TLS_CALLBACK p_thread_callback_dllmain_first_entry = on_callback;
-// The latest possible name in the .CRT$XL? (other than *Z, which has a NULL).
-#pragma const_seg(".CRT$XLY")
-extern const PIMAGE_TLS_CALLBACK p_thread_callback_dllmain_later_entry;
-const PIMAGE_TLS_CALLBACK p_thread_callback_dllmain_later_entry = on_callback;
-#pragma data_seg(pop, old_seg)
-
-#else  // _WIN64
-
-#pragma data_seg(push, old_seg)
-// Use earliest possible name in the .CRT$XL? list of segments.
-#pragma data_seg(".CRT$XLA")
-PIMAGE_TLS_CALLBACK p_thread_callback_dllmain_first_entry = on_callback;
-// The latest possible name in the .CRT$XL? (other than *Z, which has a NULL).
-#pragma data_seg(".CRT$XLY")
-PIMAGE_TLS_CALLBACK p_thread_callback_dllmain_later_entry = on_callback;
-#pragma data_seg(pop, old_seg)
-
-#endif  // _WIN64
-}  // extern "C"
-
-
-// Make DllMain call the listed callbacks.  This way any third parties that are
-// linked in will also be called.
-BOOL WINAPI DllMain(PVOID h, DWORD reason, PVOID reserved) {
-  if (DLL_THREAD_DETACH != reason && DLL_PROCESS_DETACH != reason)
-    return true;  // We won't service THREAD_ATTACH calls.
-
-  if (linker_notifications_are_active)
-    return true;  // Some other service is doing this work.
-
-  // Use our first entry as a starting point, but don't call it.
-  PIMAGE_TLS_CALLBACK* it = &p_thread_callback_dllmain_first_entry;
-  while (*++it != NULL || it < &p_thread_callback_dllmain_later_entry) {
-    if (*it == NULL || *it == on_callback)
-      continue;  // Don't bother to call our own callback.
-    (*it)(h, reason, reserved);
-  }
-  return true;
-}
-
-static void NTAPI on_callback(PVOID h, DWORD reason, PVOID reserved) {
-  // Do nothing.  We were just a place holder in the list used to test that we
-  // call all items.
-  // If we are called, it means that some other system is scanning the callbacks
-  // and we don't need to do so in DllMain().
-  linker_notifications_are_active = true;
-  // Note: If some other routine some how plays this same game... we could both
-  // decide not to do the scanning <sigh>, but this trick should suppress
-  // duplicate calls on Vista, where the runtime takes care of the callbacks,
-  // and allow us to do the callbacks on XP, where we are currently devoid of
-  // callbacks (due to an explicit LoadLibrary call).
-}