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- //===-- asan_win_dynamic_runtime_thunk.cpp --------------------------------===//
- //
- // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
- // See https://llvm.org/LICENSE.txt for license information.
- // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
- //
- //===----------------------------------------------------------------------===//
- //
- // This file is a part of AddressSanitizer, an address sanity checker.
- //
- // This file defines things that need to be present in the application modules
- // to interact with the ASan DLL runtime correctly and can't be implemented
- // using the default "import library" generated when linking the DLL RTL.
- //
- // This includes:
- // - creating weak aliases to default implementation imported from asan dll.
- // - forwarding the detect_stack_use_after_return runtime option
- // - working around deficiencies of the MD runtime
- // - installing a custom SEH handler
- //
- //===----------------------------------------------------------------------===//
- #ifdef SANITIZER_DYNAMIC_RUNTIME_THUNK
- #define SANITIZER_IMPORT_INTERFACE 1
- #include "sanitizer_common/sanitizer_win_defs.h"
- #define WIN32_LEAN_AND_MEAN
- #include <windows.h>
- // Define weak alias for all weak functions imported from asan dll.
- #define INTERFACE_FUNCTION(Name)
- #define INTERFACE_WEAK_FUNCTION(Name) WIN_WEAK_IMPORT_DEF(Name)
- #include "asan_interface.inc"
- // First, declare CRT sections we'll be using in this file
- #pragma section(".CRT$XIB", long, read)
- #pragma section(".CRT$XID", long, read)
- #pragma section(".CRT$XCAB", long, read)
- #pragma section(".CRT$XTW", long, read)
- #pragma section(".CRT$XTY", long, read)
- #pragma section(".CRT$XLAB", long, read)
- ////////////////////////////////////////////////////////////////////////////////
- // 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.
- //
- // The ASan MD runtime dllexports '__asan_option_detect_stack_use_after_return',
- // so normally we would just dllimport it. Unfortunately, the dllimport
- // attribute adds __imp_ prefix to the symbol name of a variable.
- // Since in general we don't know if a given TU is going to be used
- // 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 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;
- __declspec(dllimport) void* __asan_get_shadow_memory_dynamic_address();
- void* __asan_shadow_memory_dynamic_address;
- }
- static int InitializeClonedVariables() {
- __asan_option_detect_stack_use_after_return =
- __asan_should_detect_stack_use_after_return();
- __asan_shadow_memory_dynamic_address =
- __asan_get_shadow_memory_dynamic_address();
- return 0;
- }
- static void NTAPI asan_thread_init(void *mod, unsigned long reason,
- void *reserved) {
- if (reason == DLL_PROCESS_ATTACH) InitializeClonedVariables();
- }
- // Our cloned variables must be initialized before C/C++ constructors. If TLS
- // is used, our .CRT$XLAB initializer will run first. If not, our .CRT$XIB
- // initializer is needed as a backup.
- __declspec(allocate(".CRT$XIB")) int (*__asan_initialize_cloned_variables)() =
- InitializeClonedVariables;
- __declspec(allocate(".CRT$XLAB")) void (NTAPI *__asan_tls_init)(void *,
- unsigned long, void *) = asan_thread_init;
- ////////////////////////////////////////////////////////////////////////////////
- // 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" int __cdecl atexit(void (__cdecl *f)(void));
- extern "C" void __cdecl _initterm(void *a, void *b);
- namespace {
- __declspec(allocate(".CRT$XTW")) void* before_global_dtors = 0;
- __declspec(allocate(".CRT$XTY")) void* after_global_dtors = 0;
- void UnregisterGlobals() {
- _initterm(&before_global_dtors, &after_global_dtors);
- }
- int ScheduleUnregisterGlobals() {
- return atexit(UnregisterGlobals);
- }
- } // namespace
- // 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"))
- int (*__asan_schedule_unregister_globals)() = ScheduleUnregisterGlobals;
- ////////////////////////////////////////////////////////////////////////////////
- // 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.cpp).
- 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.
- __declspec(allocate(".CRT$XCAB")) int (*__asan_seh_interceptor)() =
- SetSEHFilter;
- }
- WIN_FORCE_LINK(__asan_dso_reg_hook)
- #endif // SANITIZER_DYNAMIC_RUNTIME_THUNK
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