Index: compiler-rt/trunk/lib/asan/CMakeLists.txt
===================================================================
--- compiler-rt/trunk/lib/asan/CMakeLists.txt
+++ compiler-rt/trunk/lib/asan/CMakeLists.txt
@@ -223,18 +223,28 @@
         SOURCES $<TARGET_OBJECTS:RTInterception.${arch}>
         PARENT_TARGET asan)
 
-      set(DYNAMIC_RUNTIME_THUNK_CFLAGS "-DASAN_DYNAMIC_RUNTIME_THUNK")
+      set(DYNAMIC_RUNTIME_THUNK_CFLAGS "-DSANITIZER_DYNAMIC_RUNTIME_THUNK")
       if(MSVC)
         list(APPEND DYNAMIC_RUNTIME_THUNK_CFLAGS "-Zl")
       elseif(CMAKE_C_COMPILER_ID MATCHES Clang)
         list(APPEND DYNAMIC_RUNTIME_THUNK_CFLAGS "-nodefaultlibs")
       endif()
 
+      add_compiler_rt_object_libraries(AsanDynamicRuntimeThunk
+        ${SANITIZER_COMMON_SUPPORTED_OS}
+        ARCHS ${ASAN_SUPPORTED_ARCH}
+        SOURCES asan_globals_win.cc
+                asan_win_dynamic_runtime_thunk.cc
+        CFLAGS ${ASAN_CFLAGS} ${DYNAMIC_RUNTIME_THUNK_CFLAGS}
+        DEFS ${ASAN_COMMON_DEFINITIONS})
+
       add_compiler_rt_runtime(clang_rt.asan_dynamic_runtime_thunk
         STATIC
         ARCHS ${arch}
-        SOURCES asan_win_dynamic_runtime_thunk.cc
-                asan_globals_win.cc
+        OBJECT_LIBS AsanDynamicRuntimeThunk
+                    UbsanDynamicRuntimeThunk
+                    SancovDynamicRuntimeThunk
+                    SanitizerCommonDynamicRuntimeThunk
         CFLAGS ${ASAN_CFLAGS} ${DYNAMIC_RUNTIME_THUNK_CFLAGS}
         DEFS ${ASAN_COMMON_DEFINITIONS}
         PARENT_TARGET asan)
Index: compiler-rt/trunk/lib/asan/asan_win_dynamic_runtime_thunk.cc
===================================================================
--- compiler-rt/trunk/lib/asan/asan_win_dynamic_runtime_thunk.cc
+++ compiler-rt/trunk/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 @@
 
 WIN_FORCE_LINK(__asan_dso_reg_hook)
 
-#endif // ASAN_DYNAMIC_RUNTIME_THUNK
+#endif // SANITIZER_DYNAMIC_RUNTIME_THUNK
Index: compiler-rt/trunk/lib/sanitizer_common/CMakeLists.txt
===================================================================
--- compiler-rt/trunk/lib/sanitizer_common/CMakeLists.txt
+++ compiler-rt/trunk/lib/sanitizer_common/CMakeLists.txt
@@ -199,6 +199,25 @@
     SOURCES sanitizer_coverage_win_dll_thunk.cc
     CFLAGS ${SANITIZER_CFLAGS} -DSANITIZER_DLL_THUNK
     DEFS ${SANITIZER_COMMON_DEFINITIONS})
+
+  set(DYNAMIC_RUNTIME_THUNK_CFLAGS "-DSANITIZER_DYNAMIC_RUNTIME_THUNK")
+  if(MSVC)
+    list(APPEND DYNAMIC_RUNTIME_THUNK_CFLAGS "-Zl")
+  elseif(CMAKE_C_COMPILER_ID MATCHES Clang)
+    list(APPEND DYNAMIC_RUNTIME_THUNK_CFLAGS "-nodefaultlibs")
+  endif()
+  add_compiler_rt_object_libraries(SanitizerCommonDynamicRuntimeThunk
+    ${SANITIZER_COMMON_SUPPORTED_OS}
+    ARCHS ${SANITIZER_COMMON_SUPPORTED_ARCH}
+    SOURCES sanitizer_win_dynamic_runtime_thunk.cc
+    CFLAGS ${SANITIZER_CFLAGS} ${DYNAMIC_RUNTIME_THUNK_CFLAGS}
+    DEFS ${SANITIZER_COMMON_DEFINITIONS})
+  add_compiler_rt_object_libraries(SancovDynamicRuntimeThunk
+    ${SANITIZER_COMMON_SUPPORTED_OS}
+    ARCHS ${SANITIZER_COMMON_SUPPORTED_ARCH}
+    SOURCES sanitizer_coverage_win_dynamic_runtime_thunk.cc
+    CFLAGS ${SANITIZER_CFLAGS} ${DYNAMIC_RUNTIME_THUNK_CFLAGS}
+    DEFS ${SANITIZER_COMMON_DEFINITIONS})
 endif()
 
 # Unit tests for common sanitizer runtime.
Index: compiler-rt/trunk/lib/sanitizer_common/sanitizer_coverage_win_dynamic_runtime_thunk.cc
===================================================================
--- compiler-rt/trunk/lib/sanitizer_common/sanitizer_coverage_win_dynamic_runtime_thunk.cc
+++ compiler-rt/trunk/lib/sanitizer_common/sanitizer_coverage_win_dynamic_runtime_thunk.cc
@@ -0,0 +1,21 @@
+//===-- sanitizer_coverage_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 Sanitizer Coverage, when it is included in a dll.
+//
+//===----------------------------------------------------------------------===//
+#ifdef SANITIZER_DYNAMIC_RUNTIME_THUNK
+#define SANITIZER_IMPORT_INTERFACE 1
+#include "sanitizer_win_defs.h"
+// Define weak alias for all weak functions imported from sanitizer coverage.
+#define INTERFACE_FUNCTION(Name)
+#define INTERFACE_WEAK_FUNCTION(Name) WIN_WEAK_IMPORT_DEF(Name)
+#include "sanitizer_coverage_interface.inc"
+#endif // SANITIZER_DYNAMIC_RUNTIME_THUNK
Index: compiler-rt/trunk/lib/sanitizer_common/sanitizer_win_dynamic_runtime_thunk.cc
===================================================================
--- compiler-rt/trunk/lib/sanitizer_common/sanitizer_win_dynamic_runtime_thunk.cc
+++ compiler-rt/trunk/lib/sanitizer_common/sanitizer_win_dynamic_runtime_thunk.cc
@@ -0,0 +1,21 @@
+//===-- santizer_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 Sanitizer Common, when it is included in a dll.
+//
+//===----------------------------------------------------------------------===//
+#ifdef SANITIZER_DYNAMIC_RUNTIME_THUNK
+#define SANITIZER_IMPORT_INTERFACE 1
+#include "sanitizer_win_defs.h"
+// Define weak alias for all weak functions imported from sanitizer common.
+#define INTERFACE_FUNCTION(Name)
+#define INTERFACE_WEAK_FUNCTION(Name) WIN_WEAK_IMPORT_DEF(Name)
+#include "sanitizer_common_interface.inc"
+#endif // SANITIZER_DYNAMIC_RUNTIME_THUNK
Index: compiler-rt/trunk/lib/ubsan/CMakeLists.txt
===================================================================
--- compiler-rt/trunk/lib/ubsan/CMakeLists.txt
+++ compiler-rt/trunk/lib/ubsan/CMakeLists.txt
@@ -97,6 +97,19 @@
       SOURCES ubsan_win_dll_thunk.cc
       CFLAGS ${UBSAN_CFLAGS} -DSANITIZER_DLL_THUNK
       DEFS ${UBSAN_COMMON_DEFINITIONS})
+
+    set(DYNAMIC_RUNTIME_THUNK_CFLAGS "-DSANITIZER_DYNAMIC_RUNTIME_THUNK")
+    if(MSVC)
+      list(APPEND DYNAMIC_RUNTIME_THUNK_CFLAGS "-Zl")
+    elseif(CMAKE_C_COMPILER_ID MATCHES Clang)
+      list(APPEND DYNAMIC_RUNTIME_THUNK_CFLAGS "-nodefaultlibs")
+    endif()
+    add_compiler_rt_object_libraries(UbsanDynamicRuntimeThunk
+      ${SANITIZER_COMMON_SUPPORTED_OS}
+      ARCHS ${UBSAN_SUPPORTED_ARCH}
+      SOURCES ubsan_win_dynamic_runtime_thunk.cc
+      CFLAGS ${UBSAN_CFLAGS} ${DYNAMIC_RUNTIME_THUNK_CFLAGS}
+      DEFS ${UBSAN_COMMON_DEFINITIONS})
   endif()
 
   if(COMPILER_RT_HAS_UBSAN)
Index: compiler-rt/trunk/lib/ubsan/ubsan_win_dynamic_runtime_thunk.cc
===================================================================
--- compiler-rt/trunk/lib/ubsan/ubsan_win_dynamic_runtime_thunk.cc
+++ compiler-rt/trunk/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