path: root/lib/asan/asan_win_dynamic_runtime_thunk.cpp
diff options
authorDimitry Andric <dim@FreeBSD.org>2019-10-23 17:52:22 +0000
committerDimitry Andric <dim@FreeBSD.org>2019-10-23 17:52:22 +0000
commit3a1720af1d7f43edc5b214cde0be11bfb94d077e (patch)
tree029e0ff2d5e3c0eaf2405fd8e669555fdf5e1297 /lib/asan/asan_win_dynamic_runtime_thunk.cpp
parent8f3cadc28cb2bb9e8f9d69eeaaea1f57f2f7b2ab (diff)
Vendor import of stripped compiler-rt trunk r375505, the last commitvendor/compiler-rt/compiler-rt-trunk-r375505vendor/compiler-rt
before the upstream Subversion repository was made read-only, and the LLVM project migrated to GitHub: https://llvm.org/svn/llvm-project/compiler-rt/trunk@375505
Notes: svn path=/vendor/compiler-rt/dist/; revision=353944 svn path=/vendor/compiler-rt/compiler-rt-r375505/; revision=353945; tag=vendor/compiler-rt/compiler-rt-trunk-r375505
Diffstat (limited to 'lib/asan/asan_win_dynamic_runtime_thunk.cpp')
1 files changed, 130 insertions, 0 deletions
diff --git a/lib/asan/asan_win_dynamic_runtime_thunk.cpp b/lib/asan/asan_win_dynamic_runtime_thunk.cpp
new file mode 100644
index 000000000000..f0b5ec9eef7f
--- /dev/null
+++ b/lib/asan/asan_win_dynamic_runtime_thunk.cpp
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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
+#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.
+#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$XIC). As this is executed before C++
+// initializers (think ctors for globals), UnregisterGlobals gets executed after
+// dtors for C++ globals.
+int (*__asan_schedule_unregister_globals)() = ScheduleUnregisterGlobals;
+// ASan SEH handling.
+// We need to set the ASan-specific SEH handler at the end of CRT initialization
+// of each module (see also asan_win.cpp).
+extern "C" {
+__declspec(dllimport) int __asan_set_seh_filter();
+static int SetSEHFilter() { return __asan_set_seh_filter(); }
+// Unfortunately, putting a pointer to __asan_set_seh_filter into
+// __asan_intercept_seh gets optimized out, so we have to use an extra function.
+__declspec(allocate(".CRT$XCAB")) int (*__asan_seh_interceptor)() =
+ SetSEHFilter;