Index: compiler-rt/trunk/lib/tsan/CMakeLists.txt
===================================================================
--- compiler-rt/trunk/lib/tsan/CMakeLists.txt
+++ compiler-rt/trunk/lib/tsan/CMakeLists.txt
@@ -25,24 +25,25 @@
 set(TSAN_SOURCES
   rtl/tsan_clock.cc
   rtl/tsan_debugging.cc
-  rtl/tsan_flags.cc
   rtl/tsan_fd.cc
+  rtl/tsan_flags.cc
   rtl/tsan_ignoreset.cc
   rtl/tsan_interceptors.cc
+  rtl/tsan_interface.cc
   rtl/tsan_interface_ann.cc
   rtl/tsan_interface_atomic.cc
-  rtl/tsan_interface.cc
   rtl/tsan_interface_java.cc
   rtl/tsan_malloc_mac.cc
   rtl/tsan_md5.cc
   rtl/tsan_mman.cc
   rtl/tsan_mutex.cc
   rtl/tsan_mutexset.cc
+  rtl/tsan_preinit.cc
   rtl/tsan_report.cc
   rtl/tsan_rtl.cc
   rtl/tsan_rtl_mutex.cc
-  rtl/tsan_rtl_report.cc
   rtl/tsan_rtl_proc.cc
+  rtl/tsan_rtl_report.cc
   rtl/tsan_rtl_thread.cc
   rtl/tsan_stack_trace.cc
   rtl/tsan_stat.cc
@@ -117,7 +118,7 @@
                 RTUbsan
     CFLAGS ${TSAN_RTL_CFLAGS}
     PARENT_TARGET tsan)
-  add_compiler_rt_object_libraries(RTTsan_dynamic 
+  add_compiler_rt_object_libraries(RTTsan_dynamic
     OS ${TSAN_SUPPORTED_OS}
     ARCHS ${TSAN_SUPPORTED_ARCH}
     SOURCES ${TSAN_SOURCES} ${TSAN_CXX_SOURCES} ${TSAN_ASM_SOURCES}
@@ -197,7 +198,7 @@
 # FreeBSD does not install a number of Clang-provided headers for the compiler
 # in the base system due to incompatibilities between FreeBSD's and Clang's
 # versions. As a workaround do not use --sysroot=. on FreeBSD until this is
-# addressed.                                                        
+# addressed.
 if(COMPILER_RT_HAS_SYSROOT_FLAG AND NOT CMAKE_SYSTEM_NAME MATCHES "FreeBSD")
   file(GLOB _tsan_generic_sources rtl/tsan*)
   file(GLOB _tsan_platform_sources rtl/tsan*posix* rtl/tsan*mac*
Index: compiler-rt/trunk/lib/tsan/rtl/tsan_preinit.cc
===================================================================
--- compiler-rt/trunk/lib/tsan/rtl/tsan_preinit.cc
+++ compiler-rt/trunk/lib/tsan/rtl/tsan_preinit.cc
@@ -0,0 +1,27 @@
+//===-- tsan_preinit.cc ---------------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file is a part of ThreadSanitizer.
+//
+// Call __tsan_init at the very early stage of process startup.
+//===----------------------------------------------------------------------===//
+
+#include "sanitizer_common/sanitizer_internal_defs.h"
+#include "tsan_interface.h"
+
+#if SANITIZER_CAN_USE_PREINIT_ARRAY
+
+// The symbol is called __local_tsan_preinit, because it's not intended to be
+// exported.
+// This code linked into the main executable when -fsanitize=thread is in
+// the link flags. It can only use exported interface functions.
+__attribute__((section(".preinit_array"), used))
+void (*__local_tsan_preinit)(void) = __tsan_init;
+
+#endif
Index: compiler-rt/trunk/test/tsan/Linux/check_preinit.cc
===================================================================
--- compiler-rt/trunk/test/tsan/Linux/check_preinit.cc
+++ compiler-rt/trunk/test/tsan/Linux/check_preinit.cc
@@ -0,0 +1,60 @@
+// RUN: %clang_tsan -fno-sanitize=thread -shared -fPIC -O1 -DBUILD_SO=1 %s -o \
+// RUN:  %t.so && \
+// RUN:   %clang_tsan -O1 %s %t.so -o %t && %run %t 2>&1 | FileCheck %s
+// RUN: llvm-objdump -t %t | FileCheck %s --check-prefix=CHECK-DUMP
+// CHECK-DUMP:  {{[.]preinit_array.*__local_tsan_preinit}}
+
+// SANITIZER_CAN_USE_PREINIT_ARRAY is undefined on android.
+// UNSUPPORTED: android
+
+// Test checks if __tsan_init is called from .preinit_array.
+// Without initialization from .preinit_array, __tsan_init will be called from
+// constructors of the binary which are called after constructors of shared
+// library.
+
+#include <stdio.h>
+
+#if BUILD_SO
+
+// "volatile" is needed to avoid compiler optimize-out constructors.
+volatile int counter = 0;
+volatile int lib_constructor_call = 0;
+volatile int tsan_init_call = 0;
+
+__attribute__ ((constructor))
+void LibConstructor() {
+  lib_constructor_call = ++counter;
+};
+
+#else  // BUILD_SO
+
+extern int counter;
+extern int lib_constructor_call;
+extern int tsan_init_call;
+
+volatile int bin_constructor_call = 0;
+
+__attribute__ ((constructor))
+void BinConstructor() {
+  bin_constructor_call = ++counter;
+};
+
+namespace __tsan {
+
+void OnInitialize() {
+  tsan_init_call = ++counter;
+}
+
+}
+
+int main() {
+  // CHECK: TSAN_INIT 1
+  // CHECK: LIB_CONSTRUCTOR 2
+  // CHECK: BIN_CONSTRUCTOR 3
+  printf("TSAN_INIT %d\n", tsan_init_call);
+  printf("LIB_CONSTRUCTOR %d\n", lib_constructor_call);
+  printf("BIN_CONSTRUCTOR %d\n", bin_constructor_call);
+  return 0;
+}
+
+#endif  // BUILD_SO