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-rw-r--r--lib/asan/asan_win_dynamic_runtime_thunk.cc94
1 files changed, 36 insertions, 58 deletions
diff --git a/lib/asan/asan_win_dynamic_runtime_thunk.cc b/lib/asan/asan_win_dynamic_runtime_thunk.cc
index 19456141c1ec..d59f9f5768a0 100644
--- a/lib/asan/asan_win_dynamic_runtime_thunk.cc
+++ b/lib/asan/asan_win_dynamic_runtime_thunk.cc
@@ -15,7 +15,8 @@
//
// This includes:
// - forwarding the detect_stack_use_after_return runtime option
-// - installing a custom SEH handler
+// - working around deficiencies of the MD runtime
+// - installing a custom SEH handlerx
//
//===----------------------------------------------------------------------===//
@@ -24,9 +25,13 @@
// simplifies the build procedure.
#ifdef ASAN_DYNAMIC_RUNTIME_THUNK
#include <windows.h>
-#include <psapi.h>
-extern "C" {
+// First, declare CRT sections we'll be using in this file
+#pragma section(".CRT$XID", long, read) // NOLINT
+#pragma section(".CRT$XIZ", long, read) // NOLINT
+#pragma section(".CRT$XTW", long, read) // NOLINT
+#pragma section(".CRT$XTY", long, read) // NOLINT
+
////////////////////////////////////////////////////////////////////////////////
// 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.
@@ -38,82 +43,55 @@ extern "C" {
// 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.
+extern "C" {
__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);
-}
+// For some reason, the MD CRT doesn't call the C/C++ terminators during on DLL
+// unload or on exit. ASan relies on LLVM global_dtors to call
+// __asan_unregister_globals on these events, which unfortunately doesn't work
+// with the MD runtime, see PR22545 for the details.
+// To work around this, for each DLL we schedule a call to UnregisterGlobals
+// using atexit() that calls a small subset of C terminators
+// where LLVM global_dtors is placed. Fingers crossed, no other C terminators
+// are there.
+extern "C" void __cdecl _initterm(void *a, void *b);
namespace {
-void *this_module_base, *this_module_end;
+__declspec(allocate(".CRT$XTW")) void* before_global_dtors = 0;
+__declspec(allocate(".CRT$XTY")) void* after_global_dtors = 0;
void UnregisterGlobals() {
- __asan::UnregisterGlobalsInRange(this_module_base, this_module_end);
+ _initterm(&before_global_dtors, &after_global_dtors);
}
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;
-
- 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).
+// We need to call 'atexit(UnregisterGlobals);' as early as possible, but after
+// atexit() is initialized (.CRT$XIC). As this is executed before C++
+// initializers (think ctors for globals), UnregisterGlobals gets executed after
+// dtors for C++ globals.
__declspec(allocate(".CRT$XID"))
-static int (*__asan_schedule_unregister_globals)() = ScheduleUnregisterGlobals;
+int (*__asan_schedule_unregister_globals)() = ScheduleUnregisterGlobals;
+} // namespace
+
+////////////////////////////////////////////////////////////////////////////////
+// ASan SEH handling.
// We need to set the ASan-specific SEH handler at the end of CRT initialization
// of each module (see also asan_win.cc).
-//
+extern "C" {
+__declspec(dllimport) int __asan_set_seh_filter();
+static int SetSEHFilter() { return __asan_set_seh_filter(); }
+
// Unfortunately, putting a pointer to __asan_set_seh_filter into
// __asan_intercept_seh gets optimized out, so we have to use an extra function.
-extern "C" __declspec(allocate(".CRT$XIZ"))
-int (*__asan_seh_interceptor)() = SetSEHFilter;
+__declspec(allocate(".CRT$XIZ")) int (*__asan_seh_interceptor)() = SetSEHFilter;
+}
#endif // ASAN_DYNAMIC_RUNTIME_THUNK