From 426cb567e0220f9a501c1b6992301e45b1bbdcbd Mon Sep 17 00:00:00 2001
From: Timur Iskhodzhanov <timurrrr@google.com>
Date: Fri, 20 Feb 2015 15:34:16 +0000
Subject: [ASan/Win] Work around PR22545 - unregister globals when using the MD
 runtime

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@230018 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/asan/asan_win_dynamic_runtime_thunk.cc | 85 ++++++++++++++++++++++++++----
 1 file changed, 76 insertions(+), 9 deletions(-)

(limited to 'lib/asan/asan_win_dynamic_runtime_thunk.cc')

diff --git a/lib/asan/asan_win_dynamic_runtime_thunk.cc b/lib/asan/asan_win_dynamic_runtime_thunk.cc
index 3a4de7dbf..19456141c 100644
--- a/lib/asan/asan_win_dynamic_runtime_thunk.cc
+++ b/lib/asan/asan_win_dynamic_runtime_thunk.cc
@@ -23,10 +23,11 @@
 // Using #ifdef rather than relying on Makefiles etc.
 // simplifies the build procedure.
 #ifdef ASAN_DYNAMIC_RUNTIME_THUNK
-extern "C" {
-__declspec(dllimport) int __asan_set_seh_filter();
-__declspec(dllimport) int __asan_should_detect_stack_use_after_return();
+#include <windows.h>
+#include <psapi.h>
 
+extern "C" {
+////////////////////////////////////////////////////////////////////////////////
 // Define a copy of __asan_option_detect_stack_use_after_return that should be
 // used when linking an MD runtime with a set of object files on Windows.
 //
@@ -37,16 +38,82 @@ __declspec(dllimport) int __asan_should_detect_stack_use_after_return();
 // with a MT or MD runtime and we don't want to use ugly __imp_ names on Windows
 // just to work around this issue, let's clone the a variable that is
 // constant after initialization anyways.
+__declspec(dllimport) int __asan_should_detect_stack_use_after_return();
 int __asan_option_detect_stack_use_after_return =
     __asan_should_detect_stack_use_after_return();
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// For some reason, the MD CRT doesn't call the C/C++ terminators as MT does.
+// To work around this, for each DLL we schedule a call to
+// UnregisterGlobalsInRange atexit() specifying the address range of the DLL
+// image to unregister globals in that range.   We don't do the same
+// for the main module (.exe) as the asan_globals.cc allocator is destroyed
+// by the time UnregisterGlobalsInRange is executed.
+// See PR22545 for the details.
+namespace __asan {
+__declspec(dllimport)
+void UnregisterGlobalsInRange(void *beg, void *end);
+}
+
+namespace {
+void *this_module_base, *this_module_end;
+
+void UnregisterGlobals() {
+  __asan::UnregisterGlobalsInRange(this_module_base, this_module_end);
+}
+
+int ScheduleUnregisterGlobals() {
+  HMODULE this_module = 0;
+  // Increments the reference counter of the DLL module, so need to call
+  // FreeLibrary later.
+  if (!GetModuleHandleEx(GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS,
+                         (LPCTSTR)&UnregisterGlobals, &this_module))
+    return 1;
+
+  // Skip the main module.
+  if (this_module == GetModuleHandle(0))
+    return 0;
+
+  MODULEINFO mi;
+  bool success =
+      GetModuleInformation(GetCurrentProcess(), this_module, &mi, sizeof(mi));
+  if (!FreeLibrary(this_module))
+    return 2;
+  if (!success)
+    return 3;
 
-// Set the ASan-specific SEH handler at the end of CRT initialization of each
-// module (see asan_win.cc for the details).
+  this_module_base = mi.lpBaseOfDll;
+  this_module_end = (char*)mi.lpBaseOfDll + mi.SizeOfImage;
+
+  return atexit(UnregisterGlobals);
+}
+}  // namespace
+
+///////////////////////////////////////////////////////////////////////////////
+// ASan SEH handling.
+extern "C" __declspec(dllimport) int __asan_set_seh_filter();
+static int SetSEHFilter() { return __asan_set_seh_filter(); }
+
+///////////////////////////////////////////////////////////////////////////////
+// We schedule some work at start-up by placing callbacks to our code to the
+// list of CRT C initializers.
+//
+// First, declare sections we'll be using:
+#pragma section(".CRT$XID", long, read)  // NOLINT
+#pragma section(".CRT$XIZ", long, read)  // NOLINT
+
+// We need to call 'atexit(UnregisterGlobals);' after atexit() is initialized
+// (.CRT$XIC) but before the C++ constructors (.CRT$XCA).
+__declspec(allocate(".CRT$XID"))
+static int (*__asan_schedule_unregister_globals)() = ScheduleUnregisterGlobals;
+
+// We need to set the ASan-specific SEH handler at the end of CRT initialization
+// of each module (see also asan_win.cc).
 //
 // Unfortunately, putting a pointer to __asan_set_seh_filter into
 // __asan_intercept_seh gets optimized out, so we have to use an extra function.
-static int SetSEHFilter() { return __asan_set_seh_filter(); }
-#pragma section(".CRT$XIZ", long, read)  // NOLINT
-__declspec(allocate(".CRT$XIZ")) int (*__asan_seh_interceptor)() = SetSEHFilter;
-}
+extern "C" __declspec(allocate(".CRT$XIZ"))
+int (*__asan_seh_interceptor)() = SetSEHFilter;
+
 #endif // ASAN_DYNAMIC_RUNTIME_THUNK
-- 
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