[sanitizer] Add dynamic_runtime_thunk for different sanitizers.

In Windows, when the sanitizer is implemented as a shared library (DLL), we need
an auxiliary static library dynamic_runtime_thunk that will be linked to the
main executable and dlls.

In the sanitizer DLL, we are exposing weak functions with WIN_WEAK_EXPORT_DEF(),
which exports the default implementation with __dll suffix. For example: for
sanitizer coverage, the default implementation of __sanitizer_cov_trace_cmp is
exported as: __sanitizer_cov_trace_cmp__dll.

In the dynamic_runtime_thunk static library, we include weak aliases to the
imported implementation from the dll, using the macro WIN_WEAK_IMPORT_DEF().

By default, all users's programs that include calls to weak functions like
__sanitizer_cov_trace_cmp, will be redirected to the implementation in the dll,
when linking to dynamic_runtime_thunk.

After this diff, we are able to compile code with sanitizer coverage
instrumentation on Windows. When the instrumented object files are linked with
clang-rt_asan_dynamic_runtime_thunk-arch.lib all the weak symbols will be
resolved to the implementation imported from asan dll.

All the files sanitizer_dynamic_runtime_thunk.cc are independent, so we do not
need to include a specific list of sanitizers.
Now, we compile: [asan|ubsan|sanitizer_coverage]_win_dynamic_runtime_thunk.cc
and sanitizer_win_dynamic_runtime_thunk.cc to generate
asan_dynamic_runtime_thunk.lib, because we include asan, ubsan and sanitizer
coverage in the address sanitizer library.

Differential Revision: https://reviews.llvm.org/D29158

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@293953 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 21 insertions, 0 deletions

diff --git a/lib/ubsan/ubsan_win_dynamic_runtime_thunk.cc b/lib/ubsan/ubsan_win_dynamic_runtime_thunk.cc
new file mode 100644
index 000000000..c9b74a4c9
--- /dev/null
+++ b/lib/ubsan/ubsan_win_dynamic_runtime_thunk.cc
@@ -0,0 +1,21 @@
+//===-- ubsan_win_dynamic_runtime_thunk.cc --------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines things that need to be present in the application modules
+// to interact with Ubsan, when it is included in a dll.
+//
+//===----------------------------------------------------------------------===//
+#ifdef SANITIZER_DYNAMIC_RUNTIME_THUNK
+#define SANITIZER_IMPORT_INTERFACE 1
+#include "sanitizer_common/sanitizer_win_defs.h"
+// Define weak alias for all weak functions imported from ubsan.
+#define INTERFACE_FUNCTION(Name)
+#define INTERFACE_WEAK_FUNCTION(Name) WIN_WEAK_IMPORT_DEF(Name)
+#include "ubsan_interface.inc"
+#endif // SANITIZER_DYNAMIC_RUNTIME_THUNK