tsan: make cur_thread_init return cur_thread

[dvyukov]

Summary

Whenever we call cur_thread_init, we call cur_thread on the next line.
So make cur_thread_init return the current thread directly.
Makes code a bit shorter, does not affect codegen.

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

private:
   void DisableIgnoresImpl();
   void EnableIgnoresImpl();
 };
 
 LibIgnore *libignore();
 
 #if !SANITIZER_GO
 inline bool in_symbolizer() {
-  cur_thread_init();
-  return UNLIKELY(cur_thread()->in_symbolizer);
+  return UNLIKELY(cur_thread_init()->in_symbolizer);
 }
 #endif
 
 }  // namespace __tsan
 
 #define SCOPED_INTERCEPTOR_RAW(func, ...)      \
-  cur_thread_init();                           \
-  ThreadState *thr = cur_thread();             \
+  ThreadState *thr = cur_thread_init();        \
   const uptr caller_pc = GET_CALLER_PC();      \
   ScopedInterceptor si(thr, #func, caller_pc); \
   const uptr pc = GET_CURRENT_PC();            \
   (void)pc;
 
 #define SCOPED_TSAN_INTERCEPTOR(func, ...)                                \
   SCOPED_INTERCEPTOR_RAW(func, __VA_ARGS__);                              \
   if (REAL(func) == 0) {                                                  \

compiler-rt/lib/tsan/rtl/tsan_interceptors_posix.cpp

 const int SA_SIGINFO = 8;
 const int SIG_SETMASK = 3;
 #else
 const int SA_SIGINFO = 4;
 const int SIG_SETMASK = 2;
 #endif
 
 #define COMMON_INTERCEPTOR_NOTHING_IS_INITIALIZED \
-  (cur_thread_init(), !cur_thread()->is_inited)
+  (!cur_thread_init()->is_inited)
 
 namespace __tsan {
 struct SignalDesc {
   bool armed;
   __sanitizer_siginfo siginfo;
   ucontext_t ctx;
 };
 
if (buf->sp == sp) {
       return;
     }
   }
   Printf("ThreadSanitizer: can't find longjmp buf\n");
   CHECK(0);
 }
 
 // FIXME: put everything below into a common extern "C" block?
-extern "C" void __tsan_setjmp(uptr sp) {
-  cur_thread_init();
-  SetJmp(cur_thread(), sp);
-}
+extern "C" void __tsan_setjmp(uptr sp) { SetJmp(cur_thread_init(), sp); }
 
 #if SANITIZER_MAC
 TSAN_INTERCEPTOR(int, setjmp, void *env);
 TSAN_INTERCEPTOR(int, _setjmp, void *env);
 TSAN_INTERCEPTOR(int, sigsetjmp, void *env);
 #else  // SANITIZER_MAC
 
 #if SANITIZER_NETBSD
struct ThreadParam {
   Semaphore started;
 };
 
 extern "C" void *__tsan_thread_start_func(void *arg) {
   ThreadParam *p = (ThreadParam*)arg;
   void* (*callback)(void *arg) = p->callback;
   void *param = p->param;
   {
-    cur_thread_init();
-    ThreadState *thr = cur_thread();
+    ThreadState *thr = cur_thread_init();
     // Thread-local state is not initialized yet.
     ScopedIgnoreInterceptors ignore;
 #if !SANITIZER_MAC && !SANITIZER_NETBSD && !SANITIZER_FREEBSD
     ThreadIgnoreBegin(thr, 0);
     if (pthread_setspecific(interceptor_ctx()->finalize_key,
                             (void *)GetPthreadDestructorIterations())) {
       Printf("ThreadSanitizer: failed to set thread key\n");
       Die();

 static bool is_sync_signal(ThreadSignalContext *sctx, int sig) {
   return sig == SIGSEGV || sig == SIGBUS || sig == SIGILL || sig == SIGTRAP ||
          sig == SIGABRT || sig == SIGFPE || sig == SIGPIPE || sig == SIGSYS ||
          // If we are sending signal to ourselves, we must process it now.
          (sctx && sig == sctx->int_signal_send);
 }
 
 void sighandler(int sig, __sanitizer_siginfo *info, void *ctx) {
-  cur_thread_init();
-  ThreadState *thr = cur_thread();
+  ThreadState *thr = cur_thread_init();
   ThreadSignalContext *sctx = SigCtx(thr);
   if (sig < 0 || sig >= kSigCount) {
     VPrintf(1, "ThreadSanitizer: ignoring signal %d\n", sig);
     return;
   }
   // Don't mess with synchronous signals.
   const bool sync = is_sync_signal(sctx, sig);
   if (sync ||

compiler-rt/lib/tsan/rtl/tsan_interface.cpp

 #include "tsan_rtl.h"
 #include "sanitizer_common/sanitizer_internal_defs.h"
 #include "sanitizer_common/sanitizer_ptrauth.h"
 
 #define CALLERPC ((uptr)__builtin_return_address(0))
 
 using namespace __tsan;
 
-void __tsan_init() {
-  cur_thread_init();
-  Initialize(cur_thread());
-}
+void __tsan_init() { Initialize(cur_thread_init()); }
 
 void __tsan_flush_memory() {
   FlushShadowMemory();
 }
 
 void __tsan_read16(void *addr) {
   uptr pc = CALLERPC;
   ThreadState *thr = cur_thread();

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

explicit ThreadState(Context *ctx, Tid tid, int unique_id, u64 epoch,
                        uptr tls_addr, uptr tls_size);
 };
 
 #if !SANITIZER_GO
 #if SANITIZER_MAC || SANITIZER_ANDROID
 ThreadState *cur_thread();
 void set_cur_thread(ThreadState *thr);
 void cur_thread_finalize();
-inline void cur_thread_init() { }
-#else
+inline ThreadState *cur_thread_init() { return cur_thread(); }
+#  else
 __attribute__((tls_model("initial-exec")))
 extern THREADLOCAL char cur_thread_placeholder[];
 inline ThreadState *cur_thread() {
   return reinterpret_cast<ThreadState *>(cur_thread_placeholder)->current;
 }
-inline void cur_thread_init() {
+inline ThreadState *cur_thread_init() {
   ThreadState *thr = reinterpret_cast<ThreadState *>(cur_thread_placeholder);
   if (UNLIKELY(!thr->current))
     thr->current = thr;
+  return thr->current;
 }
 inline void set_cur_thread(ThreadState *thr) {
   reinterpret_cast<ThreadState *>(cur_thread_placeholder)->current = thr;
 }
 inline void cur_thread_finalize() { }
-#endif  // SANITIZER_MAC || SANITIZER_ANDROID
+#  endif  // SANITIZER_MAC || SANITIZER_ANDROID
 #endif  // SANITIZER_GO
 
 class ThreadContext final : public ThreadContextBase {
  public:
   explicit ThreadContext(Tid tid);
   ~ThreadContext();
   ThreadState *thr;
   StackID creation_stack_id;

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

void InitializeMemoryProfiler() {
   MaybeSpawnBackgroundThread();
 }
 
 static void *BackgroundThread(void *arg) {
   // This is a non-initialized non-user thread, nothing to see here.
   // We don't use ScopedIgnoreInterceptors, because we want ignores to be
   // enabled even when the thread function exits (e.g. during pthread thread
   // shutdown code).
-  cur_thread_init();
-  cur_thread()->ignore_interceptors++;
+  cur_thread_init()->ignore_interceptors++;
   const u64 kMs2Ns = 1000 * 1000;
   const u64 start = NanoTime();
 
   u64 last_flush = NanoTime();
   uptr last_rss = 0;
   for (int i = 0;
       atomic_load(&ctx->stop_background_thread, memory_order_relaxed) == 0;
       i++) {