Revert "[nsan] Add nsan_preinit.cpp and make it static library only"

https://lab.llvm.org/buildbot/#/builders/66/builds/1345

This reverts commit 2cec041.

Author: vitalybuka

compiler-rt/lib/nsan/CMakeLists.txt

@@ -11,9 +11,6 @@ set(NSAN_SOURCES
   nsan_suppressions.cpp
 )
 
-set(NSAN_PREINIT_SOURCES
-  nsan_preinit.cpp)
-
 set(NSAN_HEADERS
   nsan.h
   nsan_flags.h
@@ -64,12 +61,6 @@ if(NOT APPLE)
       ADDITIONAL_HEADERS ${NSAN_HEADERS}
       CFLAGS ${NSAN_CFLAGS})
 
-  add_compiler_rt_object_libraries(RTNsan_preinit
-    ARCHS ${NSAN_SUPPORTED_ARCH}
-    SOURCES ${NSAN_PREINIT_SOURCES}
-    ADDITIONAL_HEADERS ${NSAN_HEADERS}
-    CFLAGS ${NSAN_CFLAGS})
-
   file(WRITE ${CMAKE_CURRENT_BINARY_DIR}/dummy.cpp "")
   add_compiler_rt_object_libraries(RTNsan_dynamic_version_script_dummy
     ARCHS ${NSAN_SUPPORTED_ARCH}
@@ -81,7 +72,7 @@ add_compiler_rt_runtime(
   clang_rt.nsan
   STATIC
   ARCHS ${NSAN_SUPPORTED_ARCH}
-  OBJECT_LIBS RTNsan_preinit RTNsan
+  OBJECT_LIBS RTNsan
               ${NSAN_COMMON_RUNTIME_OBJECT_LIBS}
   CFLAGS ${NSAN_CFLAGS}
   PARENT_TARGET nsan)

compiler-rt/lib/nsan/nsan.cpp

@@ -779,7 +779,7 @@ extern "C" SANITIZER_INTERFACE_ATTRIBUTE void __nsan_dump_shadow_args() {
 bool __nsan::nsan_initialized;
 bool __nsan::nsan_init_is_running;
 
-extern "C" void __nsan_init() {
+extern "C" SANITIZER_INTERFACE_ATTRIBUTE void __nsan_init() {
   CHECK(!nsan_init_is_running);
   if (nsan_initialized)
     return;
@@ -801,3 +801,8 @@ extern "C" void __nsan_init() {
   nsan_init_is_running = false;
   nsan_initialized = true;
 }
+
+#if SANITIZER_CAN_USE_PREINIT_ARRAY
+__attribute__((section(".preinit_array"),
+               used)) static void (*nsan_init_ptr)() = __nsan_init;
+#endif

compiler-rt/lib/nsan/nsan.h

@@ -32,8 +32,6 @@ using __sanitizer::uptr;
 // Private nsan interface. Used e.g. by interceptors.
 extern "C" {
 
-void __nsan_init();
-
 // This marks the shadow type of the given block of application memory as
 // unknown.
 // printf-free (see comment in nsan_interceptors.cc).