[tsan] Always initialize tsan when building shared lib

[zhuhan0]

Summary

https://reviews.llvm.org/D135925 fixed tsan to always initialize on Android, because there tsan is used as shared library.

We can generalize the fix to always initialize when building tsan shared library. This fixes the issue where we use tsan as a shared library on Linux and it failed to initialize.

[zhuhan0]

Thanks for the review!

compiler-rt/lib/tsan/rtl/CMakeLists.txt

add_compiler_rt_runtime(clang_rt.tsan
               $<TARGET_OBJECTS:RTInterception.${arch}>
               $<TARGET_OBJECTS:RTSanitizerCommon.${arch}>
               $<TARGET_OBJECTS:RTSanitizerCommonLibc.${arch}>
               $<TARGET_OBJECTS:RTSanitizerCommonCoverage.${arch}>
               $<TARGET_OBJECTS:RTSanitizerCommonSymbolizer.${arch}>
               $<TARGET_OBJECTS:RTUbsan.${arch}>
       ADDITIONAL_HEADERS ${TSAN_HEADERS}
       CFLAGS ${TSAN_RTL_DYNAMIC_CFLAGS}
+      DEFS SANITIZER_SHARED
       LINK_LIBS ${TSAN_DYNAMIC_LINK_LIBS}
       LINK_FLAGS ${SANITIZER_COMMON_LINK_FLAGS}
       PARENT_TARGET tsan)
     add_sanitizer_rt_symbols(clang_rt.tsan
       ARCHS ${arch}
       EXTRA tsan.syms.extra)
     add_sanitizer_rt_symbols(clang_rt.tsan_cxx
       ARCHS ${arch}

compiler-rt/lib/tsan/rtl/tsan_rtl.h

 
 extern bool is_initialized;
 
 ALWAYS_INLINE
 void LazyInitialize(ThreadState *thr) {
   // If we can use .preinit_array, assume that __tsan_init
   // called from .preinit_array initializes runtime before
   // any instrumented code except ANDROID.
-#if (!SANITIZER_CAN_USE_PREINIT_ARRAY || defined(__ANDROID__))
+#if (!SANITIZER_CAN_USE_PREINIT_ARRAY || defined(SANITIZER_SHARED))
   if (UNLIKELY(!is_initialized))
     Initialize(thr);
 #endif
 }
 
 void TraceResetForTesting();
 void TraceSwitchPart(ThreadState *thr);
 void TraceSwitchPartImpl(ThreadState *thr);