diff options
Diffstat (limited to 'compiler-rt/lib/asan/asan_win_dynamic_runtime_thunk.cpp')
-rw-r--r-- | compiler-rt/lib/asan/asan_win_dynamic_runtime_thunk.cpp | 130 |
1 files changed, 130 insertions, 0 deletions
diff --git a/compiler-rt/lib/asan/asan_win_dynamic_runtime_thunk.cpp b/compiler-rt/lib/asan/asan_win_dynamic_runtime_thunk.cpp new file mode 100644 index 000000000000..f0b5ec9eef7f --- /dev/null +++ b/compiler-rt/lib/asan/asan_win_dynamic_runtime_thunk.cpp @@ -0,0 +1,130 @@ +//===-- 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 |