[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, 9 insertions, 5 deletions

diff --git a/lib/asan/asan_win_dynamic_runtime_thunk.cc b/lib/asan/asan_win_dynamic_runtime_thunk.cc
index f9b4c3f51..416c73b23 100644
--- a/lib/asan/asan_win_dynamic_runtime_thunk.cc
+++ b/lib/asan/asan_win_dynamic_runtime_thunk.cc
@@ -14,20 +14,24 @@
 // 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
 //
 //===----------------------------------------------------------------------===//
 
-// Only compile this code when building asan_dynamic_runtime_thunk.lib
-// Using #ifdef rather than relying on Makefiles etc.
-// simplifies the build procedure.
-#ifdef ASAN_DYNAMIC_RUNTIME_THUNK
+#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$XIB", long, read)  // NOLINT
 #pragma section(".CRT$XID", long, read)  // NOLINT
@@ -124,4 +128,4 @@ __declspec(allocate(".CRT$XCAB")) int (*__asan_seh_interceptor)() =
 
 WIN_FORCE_LINK(__asan_dso_reg_hook)
 
-#endif // ASAN_DYNAMIC_RUNTIME_THUNK
+#endif // SANITIZER_DYNAMIC_RUNTIME_THUNK