Index: CMakeLists.txt
===================================================================
--- CMakeLists.txt
+++ CMakeLists.txt
@@ -230,6 +230,8 @@
 # COMPILER_RT_DEBUG_PYBOOL is used by lit.common.configured.in.
 pythonize_bool(COMPILER_RT_DEBUG)
 
+option(COMPILER_RT_INCLUDE_ASAN_SHARED "Build shared version of AddressSanitizer runtime" OFF)
+
 #================================
 # Setup Compiler Flags
 #================================
Index: cmake/Modules/AddCompilerRT.cmake
===================================================================
--- cmake/Modules/AddCompilerRT.cmake
+++ cmake/Modules/AddCompilerRT.cmake
@@ -37,6 +37,32 @@
     COMPILE_DEFINITIONS ${LIB_DEFS})
 endmacro()
 
+# Adds shared runtime for a given architecture and puts it in the proper
+# directory in the build and install trees.
+# add_compiler_rt_shared_runtime(<name> <arch>
+#                                SOURCES <source files>
+#                                CFLAGS <compile flags>
+#                                DEFS <compile definitions>)
+macro(add_compiler_rt_shared_runtime name arch)
+  if(CAN_TARGET_${arch})
+    parse_arguments(LIB "SOURCES;CFLAGS;DEFS" "" ${ARGN})
+    add_library(${name} SHARED ${LIB_SOURCES})
+    # Setup compile flags and definitions.
+    set_target_compile_flags(${name}
+      ${TARGET_${arch}_CFLAGS} ${LIB_CFLAGS})
+    set_property(TARGET ${name} APPEND PROPERTY
+      COMPILE_DEFINITIONS ${LIB_DEFS})
+    # Setup correct output directory in the build tree.
+    set_target_properties(${name} PROPERTIES
+      LIBRARY_OUTPUT_DIRECTORY ${COMPILER_RT_LIBRARY_OUTPUT_DIR})
+    # Add installation command.
+    install(TARGETS ${name}
+      LIBRARY DESTINATION ${COMPILER_RT_LIBRARY_INSTALL_DIR})
+  else()
+    message(FATAL_ERROR "Archtecture ${arch} can't be targeted")
+  endif()
+endmacro()
+
 # Adds static runtime for a given architecture and puts it in the proper
 # directory in the build and install trees.
 # add_compiler_rt_static_runtime(<name> <arch>
Index: lib/asan/CMakeLists.txt
===================================================================
--- lib/asan/CMakeLists.txt
+++ lib/asan/CMakeLists.txt
@@ -21,7 +21,6 @@
   asan_new_delete.cc
   asan_poisoning.cc
   asan_posix.cc
-  asan_preinit.cc
   asan_report.cc
   asan_rtl.cc
   asan_stack.cc
@@ -29,6 +28,9 @@
   asan_thread.cc
   asan_win.cc)
 
+set(ASAN_PREINIT_SOURCES
+  asan_preinit.cc)
+
 include_directories(..)
 
 if(ANDROID)
@@ -69,8 +71,18 @@
 else()
   foreach(arch ${ASAN_SUPPORTED_ARCH})
     add_compiler_rt_object_library(RTAsan ${arch}
-      SOURCES ${ASAN_SOURCES} CFLAGS ${ASAN_CFLAGS}
+      SOURCES ${ASAN_SOURCES} ${ASAN_PREINIT_SOURCES} CFLAGS ${ASAN_CFLAGS}
       DEFS ${ASAN_COMMON_DEFINITIONS})
+    if (COMPILER_RT_INCLUDE_ASAN_DYNAMIC)
+      set(ASAN_DYNAMIC_DEFINITIONS
+        ${ASAN_COMMON_DEFINITIONS} ASAN_DYNAMIC)
+      add_compiler_rt_object_library(RTAsan_preinit ${arch}
+        SOURCES ${ASAN_PREINIT_SOURCES} CFLAGS ${ASAN_CFLAGS}
+        DEFS ${ASAN_COMMON_DEFINITIONS})
+      add_compiler_rt_object_library(RTAsan_dynamic ${arch}
+        SOURCES ${ASAN_SOURCES} CFLAGS ${ASAN_CFLAGS}
+        DEFS ${ASAN_DYNAMIC_DEFINITIONS})
+    endif()
   endforeach()
 endif()
 
@@ -108,24 +120,53 @@
 else()
   # Build separate libraries for each target.
   foreach(arch ${ASAN_SUPPORTED_ARCH})
-    set(ASAN_RUNTIME_OBJECTS
-      $<TARGET_OBJECTS:RTAsan.${arch}>
+    set(ASAN_COMMON_RUNTIME_OBJECTS
       $<TARGET_OBJECTS:RTInterception.${arch}>
       $<TARGET_OBJECTS:RTSanitizerCommon.${arch}>
       $<TARGET_OBJECTS:RTSanitizerCommonLibc.${arch}>)
     if (NOT WIN32)
       # We can't build Leak Sanitizer on Windows yet.
-      list(APPEND ASAN_RUNTIME_OBJECTS $<TARGET_OBJECTS:RTLSanCommon.${arch}>)
+      list(APPEND ASAN_COMMON_RUNTIME_OBJECTS $<TARGET_OBJECTS:RTLSanCommon.${arch}>)
     endif()
 
+    set(ASAN_RUNTIME_OBJECTS
+      $<TARGET_OBJECTS:RTAsan.${arch}>
+      ${ASAN_COMMON_RUNTIME_OBJECTS})
+
     add_compiler_rt_static_runtime(clang_rt.asan-${arch} ${arch}
       SOURCES ${ASAN_RUNTIME_OBJECTS}
       CFLAGS ${ASAN_CFLAGS}
       DEFS ${ASAN_COMMON_DEFINITIONS})
-    add_dependencies(asan clang_rt.asan-${arch})
+    add_dependencies(asan clang_rt.asan-${arch} clang_rt.asan-${arch})
+
+    if (COMPILER_RT_INCLUDE_ASAN_DYNAMIC)
+      set(ASAN_DYNAMIC_RUNTIME_OBJECTS
+        $<TARGET_OBJECTS:RTAsan_dynamic.${arch}>
+        ${ASAN_COMMON_RUNTIME_OBJECTS})
+      add_compiler_rt_shared_runtime(clang_rt.asan-${arch}-dynamic ${arch}
+        SOURCES ${ASAN_DYNAMIC_RUNTIME_OBJECTS}
+        CFLAGS ${ASAN_CFLAGS}
+        DEFS ${ASAN_DYNAMIC_DEFINITIONS})
+      target_link_libraries(clang_rt.asan-${arch}-dynamic pthread stdc++ dl m c)
+      add_dependencies(asan clang_rt.asan-${arch}-dynamic)
+
+      set(ASAN_PREINIT_RUNTIME_OBJECTS
+        $<TARGET_OBJECTS:RTAsan_preinit.${arch}>)
+      add_compiler_rt_static_runtime(clang_rt.asan-${arch}-preinit ${arch}
+        SOURCES ${ASAN_PREINIT_RUNTIME_OBJECTS}
+        CFLAGS ${ASAN_CFLAGS}
+        DEFS ${ASAN_DYNAMIC_DEFINITIONS})
+      add_dependencies(asan clang_rt.asan-${arch}-preinit)
+    endif()
+
     if (UNIX AND NOT ${arch} STREQUAL "i386")
       add_sanitizer_rt_symbols(clang_rt.asan-${arch} asan.syms.extra)
       add_dependencies(asan clang_rt.asan-${arch}-symbols)
+
+      if (COMPILER_RT_INCLUDE_ASAN_DYNAMIC)
+        add_sanitizer_rt_symbols(clang_rt.asan-${arch}-dynamic asan.syms.extra)
+        add_dependencies(asan clang_rt.asan-${arch}-dynamic-symbols)
+      endif()
     endif()
 
     if (WIN32)
Index: lib/asan/asan_interface_internal.h
===================================================================
--- lib/asan/asan_interface_internal.h
+++ lib/asan/asan_interface_internal.h
@@ -30,8 +30,8 @@
   // v2=>v3: stack frame description (created by the compiler)
   //         contains the function PC as the 3-rd field (see
   //         DescribeAddressIfStack).
-  SANITIZER_INTERFACE_ATTRIBUTE void __asan_init_v3();
   #define __asan_init __asan_init_v3
+  SANITIZER_INTERFACE_ATTRIBUTE void __asan_init_v3();
 
   // This structure describes an instrumented global variable.
   struct __asan_global {
Index: lib/asan/asan_internal.h
===================================================================
--- lib/asan/asan_internal.h
+++ lib/asan/asan_internal.h
@@ -70,6 +70,12 @@
 // asan_linux.cc / asan_mac.cc / asan_win.cc
 void *AsanDoesNotSupportStaticLinkage();
 
+// asan_linux.cc / asan_mac.cc / asan_win.cc
+void AsanCheckDynamicRTPrereqs();
+
+// asan_linux.cc / asan_mac.cc / asan_win.cc
+void AsanCheckIncompatibleRT();
+
 void GetPcSpBp(void *context, uptr *pc, uptr *sp, uptr *bp);
 void AsanOnSIGSEGV(int, void *siginfo, void *context);
 
Index: lib/asan/asan_linux.cc
===================================================================
--- lib/asan/asan_linux.cc
+++ lib/asan/asan_linux.cc
@@ -35,12 +35,13 @@
 
 #if SANITIZER_ANDROID
 #include <ucontext.h>
+extern "C" void* _DYNAMIC;
 #else
 #include <sys/ucontext.h>
+#include <dlfcn.h>
+#include <link.h>
 #endif
 
-extern "C" void* _DYNAMIC;
-
 namespace __asan {
 
 void MaybeReexec() {
@@ -52,6 +53,51 @@
   return &_DYNAMIC;  // defined in link.h
 }
 
+static int DsoCallback(struct dl_phdr_info *info, size_t size,
+                       void *data) {
+  // Continue until the first dynamic library is found
+  if (!info->dlpi_name || info->dlpi_name[0] == 0)
+    return 0;
+
+  *(const char **)data = info->dlpi_name;
+  return 1;
+}
+
+void AsanCheckDynamicRTPrereqs() {
+  // FIXME: can we do something like this for Android?
+#if !SANITIZER_ANDROID
+  // Asan dynamic RT should be the first dynamic library in the list
+  const char *first_library_name = 0;
+  dl_iterate_phdr(DsoCallback, &first_library_name);
+  if (first_library_name
+      && !internal_strstr(first_library_name, "libclang_rt.asan")
+      && !internal_strstr(first_library_name, "libasan.so")) {
+    Report(
+      "ASan runtime does not come first in initial library list; "
+      "you should either link to your application or "
+      "manually preload it with LD_PRELOAD.\n");
+    Die();
+  }
+
+#endif
+}
+
+void AsanCheckIncompatibleRT() {
+#if !SANITIZER_ANDROID
+  const char *badsym;
+#if ASAN_DYNAMIC
+    badsym = "__asan_static";
+#else
+    badsym = "__asan_dynamic";
+#endif
+  if (dlsym(RTLD_DEFAULT, badsym)) {
+    Report("Your application is linked against "
+      "incompatible ASan runtimes.\n");
+    Die();
+  }
+#endif
+}
+
 void GetPcSpBp(void *context, uptr *pc, uptr *sp, uptr *bp) {
 #if defined(__arm__)
   ucontext_t *ucontext = (ucontext_t*)context;
Index: lib/asan/asan_mac.cc
===================================================================
--- lib/asan/asan_mac.cc
+++ lib/asan/asan_mac.cc
@@ -199,6 +199,14 @@
   return 0;
 }
 
+// Likewise.
+void AsanCheckDynamicRTPrereqs() {
+}
+
+// Likewise.
+void AsanCheckIncompatibleRT() {
+}
+
 bool AsanInterceptsSignal(int signum) {
   return (signum == SIGSEGV || signum == SIGBUS) &&
          common_flags()->handle_segv;
Index: lib/asan/asan_rtl.cc
===================================================================
--- lib/asan/asan_rtl.cc
+++ lib/asan/asan_rtl.cc
@@ -553,6 +553,24 @@
   AsanInitInternal();
 }
 
+#ifdef ASAN_DYNAMIC
+// Initialize runtime in case it's LD_PRELOAD-ed into unsanitized executable
+// (and thus normal initializer from .preinit_array haven't run).
+
+class AsanInitializer {
+public:  // NOLINT
+  AsanInitializer() {
+    AsanCheckIncompatibleRT();
+    if (!asan_inited) {
+      AsanCheckDynamicRTPrereqs();
+      __asan_init();
+    }
+  }
+};
+
+static AsanInitializer asan_initializer;
+#endif
+
 }  // namespace __asan
 
 // ---------------------- Interface ---------------- {{{1
@@ -604,6 +622,17 @@
 // Initialize as requested from instrumented application code.
 // We use this call as a trigger to wake up ASan from deactivated state.
 void __asan_init() {
+  AsanCheckIncompatibleRT();
   AsanActivate();
   AsanInitInternal();
 }
+
+extern "C" {
+SANITIZER_INTERFACE_ATTRIBUTE
+#ifdef ASAN_DYNAMIC
+int __asan_dynamic;
+#else
+int __asan_static;
+#endif
+};
+
Index: lib/asan/asan_win.cc
===================================================================
--- lib/asan/asan_win.cc
+++ lib/asan/asan_win.cc
@@ -70,6 +70,12 @@
   return 0;
 }
 
+void AsanCheckDynamicRTPrereqs() {
+}
+
+void AsanCheckIncompatibleRT() {
+}
+
 void AsanPlatformThreadInit() {
   // Nothing here for now.
 }
Index: lib/sanitizer_common/sanitizer_internal_defs.h
===================================================================
--- lib/sanitizer_common/sanitizer_internal_defs.h
+++ lib/sanitizer_common/sanitizer_internal_defs.h
@@ -147,7 +147,12 @@
 # define FORMAT(f, a)  __attribute__((format(printf, f, a)))
 # define NOINLINE __attribute__((noinline))
 # define NORETURN  __attribute__((noreturn))
-# define THREADLOCAL   __thread
+# ifdef ASAN_DYNAMIC
+#  define THREADLOCAL __thread __attribute__((tls_model("initial-exec")))
+# else
+// FIXME: mark as local-exec?
+#  define THREADLOCAL __thread
+# endif
 # define NOTHROW throw()
 # define LIKELY(x)     __builtin_expect(!!(x), 1)
 # define UNLIKELY(x)   __builtin_expect(!!(x), 0)
Index: test/asan/CMakeLists.txt
===================================================================
--- test/asan/CMakeLists.txt
+++ test/asan/CMakeLists.txt
@@ -21,29 +21,51 @@
   set(ASAN_TEST_CONFIG_SUFFIX "64")
   set(ASAN_TEST_BITS "64")
   set(ASAN_TEST_TARGET_CFLAGS ${TARGET_64_BIT_CFLAGS})
+  set(ASAN_TEST_DYNAMIC False)
   configure_lit_site_cfg(
     ${CMAKE_CURRENT_SOURCE_DIR}/lit.site.cfg.in
     ${CMAKE_CURRENT_BINARY_DIR}/64bitConfig/lit.site.cfg
     )
   list(APPEND ASAN_TESTSUITES ${CMAKE_CURRENT_BINARY_DIR}/64bitConfig)
+  if(COMPILER_RT_INCLUDE_ASAN_DYNAMIC)
+    set(ASAN_TEST_DYNAMIC True)
+    configure_lit_site_cfg(
+      ${CMAKE_CURRENT_SOURCE_DIR}/lit.site.cfg.in
+      ${CMAKE_CURRENT_BINARY_DIR}/64bitConfig-dynamic/lit.site.cfg)
+    list(APPEND ASAN_TESTSUITES ${CMAKE_CURRENT_BINARY_DIR}/64bitConfig-dynamic)
+  endif()
 endif()
 
 if(CAN_TARGET_i386)
   set(ASAN_TEST_CONFIG_SUFFIX "32")
   set(ASAN_TEST_BITS "32")
   set(ASAN_TEST_TARGET_CFLAGS ${TARGET_32_BIT_CFLAGS})
+  set(ASAN_TEST_DYNAMIC False)
   configure_lit_site_cfg(
     ${CMAKE_CURRENT_SOURCE_DIR}/lit.site.cfg.in
     ${CMAKE_CURRENT_BINARY_DIR}/32bitConfig/lit.site.cfg
     )
   list(APPEND ASAN_TESTSUITES ${CMAKE_CURRENT_BINARY_DIR}/32bitConfig)
+  if(COMPILER_RT_INCLUDE_ASAN_DYNAMIC)
+    set(ASAN_TEST_DYNAMIC True)
+    configure_lit_site_cfg(
+      ${CMAKE_CURRENT_SOURCE_DIR}/lit.site.cfg.in
+      ${CMAKE_CURRENT_BINARY_DIR}/32bitConfig-dynamic/lit.site.cfg)
+    list(APPEND ASAN_TESTSUITES ${CMAKE_CURRENT_BINARY_DIR}/32bitConfig-dynamic)
+  endif()
 endif()
 
 if(COMPILER_RT_INCLUDE_TESTS)
-configure_lit_site_cfg(
-  ${CMAKE_CURRENT_SOURCE_DIR}/Unit/lit.site.cfg.in
-  ${CMAKE_CURRENT_BINARY_DIR}/Unit/lit.site.cfg
-  )
+  set(ASAN_TEST_DYNAMIC False)
+  configure_lit_site_cfg(
+    ${CMAKE_CURRENT_SOURCE_DIR}/Unit/lit.site.cfg.in
+    ${CMAKE_CURRENT_BINARY_DIR}/Unit/lit.site.cfg)
+  if(COMPILER_RT_INCLUDE_ASAN_DYNAMIC)
+    set(ASAN_TEST_DYNAMIC True)
+    configure_lit_site_cfg(
+      ${CMAKE_CURRENT_SOURCE_DIR}/Unit/lit.site.cfg.in
+      ${CMAKE_CURRENT_BINARY_DIR}/Unit-dynamic/lit.site.cfg)
+  endif()
 endif()
 
 set(ASAN_TEST_DEPS ${SANITIZER_COMMON_LIT_TEST_DEPS})
@@ -55,6 +77,9 @@
 if(COMPILER_RT_INCLUDE_TESTS AND NOT CAN_TARGET_arm_android)
   list(APPEND ASAN_TEST_DEPS AsanUnitTests)
   list(APPEND ASAN_TESTSUITES ${CMAKE_CURRENT_BINARY_DIR}/Unit)
+  if(COMPILER_RT_INCLUDE_ASAN_DYNAMIC)
+    list(APPEND ASAN_TESTSUITES ${CMAKE_CURRENT_BINARY_DIR}/Unit-dynamic)
+  endif()
 endif()
 add_lit_testsuite(check-asan "Running the AddressSanitizer tests"
   ${ASAN_TESTSUITES}
Index: test/asan/TestCases/Linux/DynamicRT/asan_dlopen_test.cc
===================================================================
--- test/asan/TestCases/Linux/DynamicRT/asan_dlopen_test.cc
+++ test/asan/TestCases/Linux/DynamicRT/asan_dlopen_test.cc
@@ -0,0 +1,14 @@
+// Test that dlopen of runtime is detected.
+//
+// RUN: %clangxx %s -DRT=\"%shared_libasan\" -o %t -ldl
+// RUN: not %t 2>&1 | FileCheck %s
+
+#include <dlfcn.h>
+
+int main(int argc, char **argv) {
+  dlopen(RT, RTLD_LAZY);
+  return 0;
+}
+
+// CHECK: ASan runtime does not come first in initial library list
+
Index: test/asan/TestCases/Linux/DynamicRT/asan_preload_test-1.cc
===================================================================
--- test/asan/TestCases/Linux/DynamicRT/asan_preload_test-1.cc
+++ test/asan/TestCases/Linux/DynamicRT/asan_preload_test-1.cc
@@ -0,0 +1,25 @@
+// Test if legacy executables work with sanitized shared libs
+// and preloaded runtime.
+//
+// RUN: %clangxx -DBUILD_SO=1 -fPIC -shared %s -o %t.so
+// RUN: %clangxx %s %t.so -o %t
+//
+// RUN: %clangxx_asan -DBUILD_SO=1 -fPIC -shared %s -o %t.so
+// RUN: LD_PRELOAD=%shared_libasan not %t 2>&1 | FileCheck %s
+
+#if BUILD_SO
+char dummy;
+void do_access(const void *p) {
+  // CHECK: AddressSanitizer: heap-buffer-overflow
+  dummy = ((const char *)p)[1];
+}
+#else
+#include <stdlib.h>
+extern void do_access(const void *p);
+int main(int argc, char **argv) {
+  void *p = malloc(1);
+  do_access(p);
+  free(p);
+  return 0;
+}
+#endif
Index: test/asan/TestCases/Linux/DynamicRT/asan_preload_test-2.cc
===================================================================
--- test/asan/TestCases/Linux/DynamicRT/asan_preload_test-2.cc
+++ test/asan/TestCases/Linux/DynamicRT/asan_preload_test-2.cc
@@ -0,0 +1,20 @@
+// Test that preloaded runtime works with unsanitized executables.
+//
+// RUN: %clangxx %s -o %t
+// RUN: LD_PRELOAD=%shared_libasan not %t 2>&1 | FileCheck %s
+
+#include <stdlib.h>
+
+extern "C" void *memset(void *p, int val, size_t n);
+
+void do_access(void *p) {
+  // CHECK: AddressSanitizer: heap-buffer-overflow
+  memset(p, 0, 2);
+}
+
+int main(int argc, char **argv) {
+  void *p = malloc(1);
+  do_access(p);
+  return 0;
+}
+
Index: test/asan/TestCases/Linux/DynamicRT/asan_rt_confict_test-1.cc
===================================================================
--- test/asan/TestCases/Linux/DynamicRT/asan_rt_confict_test-1.cc
+++ test/asan/TestCases/Linux/DynamicRT/asan_rt_confict_test-1.cc
@@ -0,0 +1,11 @@
+// Test that incompatible runtimes are detected.
+//
+// RUN: %clangxx_asan_static %s -o %t
+// RUN: LD_PRELOAD=%shared_libasan not %t 2>&1 | FileCheck %s
+
+#include <stdlib.h>
+int main(int argc, char **argv) {
+  return 0;
+}
+
+// CHECK: Your application is linked against incompatible ASan runtimes
Index: test/asan/TestCases/Linux/DynamicRT/lit.local.cfg
===================================================================
--- test/asan/TestCases/Linux/DynamicRT/lit.local.cfg
+++ test/asan/TestCases/Linux/DynamicRT/lit.local.cfg
@@ -0,0 +1,3 @@
+if not config.asan_dynamic:
+  config.unsupported = True
+
Index: test/asan/TestCases/Linux/interception_malloc_test.cc
===================================================================
--- test/asan/TestCases/Linux/interception_malloc_test.cc
+++ test/asan/TestCases/Linux/interception_malloc_test.cc
@@ -9,7 +9,9 @@
 #include <unistd.h>
 
 extern "C" void *__interceptor_malloc(size_t size);
-extern "C" void *malloc(size_t size) {
+extern "C"
+__attribute__((no_sanitize_address))  // Malloc may be called from dlsym in __asan_init
+void *malloc(size_t size) {
   write(2, "malloc call\n", sizeof("malloc call\n") - 1);
   return __interceptor_malloc(size);
 }
Index: test/asan/TestCases/sanity_check_pure_c.c
===================================================================
--- test/asan/TestCases/sanity_check_pure_c.c
+++ test/asan/TestCases/sanity_check_pure_c.c
@@ -3,7 +3,7 @@
 // RUN: not %t 2>&1 | FileCheck %s
 
 // Sanity checking a test in pure C with -pie.
-// RUN: %clang_asan -O2 %s -pie -o %t
+// RUN: %clang_asan -O2 %s -pie -fPIE -o %t
 // RUN: not %t 2>&1 | FileCheck %s
 
 #include <stdlib.h>
Index: test/asan/TestCases/start-deactivated.cc
===================================================================
--- test/asan/TestCases/start-deactivated.cc
+++ test/asan/TestCases/start-deactivated.cc
@@ -7,6 +7,10 @@
 // RUN: %clangxx -O0 %s -c -o %t.o
 // RUN: %clangxx_asan -O0 %t.o -o %t
 // RUN: ASAN_OPTIONS=start_deactivated=1 not %t 2>&1 | FileCheck %s
+//
+// dlsym's that check for __asan_static/__asan_dynamic call dlerror
+// which in turn calls malloc which activates Asan:
+// XFAIL: *
 
 #include <dlfcn.h>
 #include <stdio.h>
Index: test/asan/Unit/lit.site.cfg.in
===================================================================
--- test/asan/Unit/lit.site.cfg.in
+++ test/asan/Unit/lit.site.cfg.in
@@ -12,6 +12,7 @@
 # FIXME: De-hardcode this path.
 config.test_exec_root = "@COMPILER_RT_BINARY_DIR@/lib/asan/tests"
 config.test_source_root = config.test_exec_root
+config.asan_dynamic = @ASAN_TEST_DYNAMIC@
 
 # Enable leak detection in ASan unit tests on x86_64-linux.
 if config.host_os == 'Linux' and config.host_arch == 'x86_64':
Index: test/asan/lit.cfg
===================================================================
--- test/asan/lit.cfg
+++ test/asan/lit.cfg
@@ -11,6 +11,11 @@
       "to lit.site.cfg " % attr_name)
   return attr_value
 
+def push_ld_library_path(config, new_path):
+  new_ld_library_path = os.path.pathsep.join(
+    (new_path, config.environment['LD_LIBRARY_PATH']))
+  config.environment['LD_LIBRARY_PATH'] = new_ld_library_path
+
 # Setup config name.
 config.name = 'AddressSanitizer' + config.name_suffix
 
@@ -34,6 +39,12 @@
                      "-g"] + target_cflags
 clang_asan_cxxflags = config.cxx_mode_flags + clang_asan_cflags
 
+if config.asan_dynamic:
+  clang_asan_static_cflags = list(clang_asan_cflags)
+  clang_asan_cflags.append('-shared-libasan')
+  clang_asan_static_cxxflags = list(clang_asan_cxxflags)
+  clang_asan_cxxflags.append('-shared-libasan')
+
 asan_lit_source_dir = get_required_attr(config, "asan_lit_source_dir")
 if config.android == "TRUE":
   config.available_features.add('android')
@@ -49,6 +60,10 @@
 config.substitutions.append( ("%clangxx ", build_invocation(target_cxxflags)) )
 config.substitutions.append( ("%clang_asan ", build_invocation(clang_asan_cflags)) )
 config.substitutions.append( ("%clangxx_asan ", build_invocation(clang_asan_cxxflags)) )
+config.substitutions.append( ("%shared_libasan", "libclang_rt.asan-%s-dynamic.so" % config.host_arch))
+if config.asan_dynamic:
+  config.substitutions.append( ("%clang_asan_static ", build_invocation(clang_asan_static_cflags)) )
+  config.substitutions.append( ("%clangxx_asan_static ", build_invocation(clang_asan_static_cxxflags)) )
 
 # FIXME: De-hardcode this path.
 asan_source_dir = os.path.join(
@@ -69,14 +84,16 @@
 if config.host_os == 'Linux' and config.bits == '64':
   config.environment['ASAN_OPTIONS'] = 'detect_leaks=1'
 
-# GCC-ASan uses dynamic runtime by default, so we have to set LD_LIBRARY_PATH
-# to pick it up properly.
+# Set LD_LIBRARY_PATH to pick dynamic runtime up properly.
+if config.asan_dynamic:
+  libasan_dir = config.compiler_rt_libdir
+  push_ld_library_path(config, libasan_dir)
+
+# GCC-ASan uses dynamic runtime by default.
 if config.compiler_id == 'GNU':
   gcc_dir = os.path.dirname(config.clang)
   libasan_dir = os.path.join(gcc_dir, "..", "lib" + config.bits)
-  new_ld_library_path = os.path.pathsep.join(
-    (libasan_dir, config.environment['LD_LIBRARY_PATH']))
-  config.environment['LD_LIBRARY_PATH'] = new_ld_library_path
+  push_ld_library_path(config, libasan_dir)
 
 # Default test suffixes.
 config.suffixes = ['.c', '.cc', '.cpp']
Index: test/asan/lit.site.cfg.in
===================================================================
--- test/asan/lit.site.cfg.in
+++ test/asan/lit.site.cfg.in
@@ -9,6 +9,7 @@
 config.llvm_tools_dir = "@ASAN_TEST_LLVM_TOOLS_DIR@"
 config.bits = "@ASAN_TEST_BITS@"
 config.android = "@CAN_TARGET_arm_android@"
+config.asan_dynamic = @ASAN_TEST_DYNAMIC@
 
 # Load common config for all compiler-rt lit tests.
 lit_config.load_config(config, "@COMPILER_RT_BINARY_DIR@/test/lit.common.configured")
Index: test/lit.common.configured.in
===================================================================
--- test/lit.common.configured.in
+++ test/lit.common.configured.in
@@ -20,6 +20,7 @@
 set_default("compiler_rt_arch", "@COMPILER_RT_SUPPORTED_ARCH@")
 set_default("python_executable", "@PYTHON_EXECUTABLE@")
 set_default("compiler_rt_debug", @COMPILER_RT_DEBUG_PYBOOL@)
+set_default("compiler_rt_libdir", "@COMPILER_RT_LIBRARY_OUTPUT_DIR@")
 
 # LLVM tools dir can be passed in lit parameters, so try to
 # apply substitution.