tsan: remove sleeps from tests

Even sleep(1) lead to episodical flakes on some machines.
Use an invisible by tsan barrier to enforce required execution order instead.
This makes the tests deterministic and faster.



git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@226659 91177308-0d34-0410-b5e6-96231b3b80d8

96 files changed, 476 insertions, 425 deletions

diff --git a/test/tsan/atomic_free.cc b/test/tsan/atomic_free.cc
index 1dcf887c4..a0d8e426b 100644
--- a/test/tsan/atomic_free.cc
+++ b/test/tsan/atomic_free.cc
@@ -1,17 +1,18 @@
 // RUN: %clangxx_tsan -O1 %s -o %t && %deflake %run %t | FileCheck %s
-#include <pthread.h>
-#include <unistd.h>
+#include "test.h"
 
 void *Thread(void *a) {
   __atomic_fetch_add((int*)a, 1, __ATOMIC_SEQ_CST);
+  barrier_wait(&barrier);
   return 0;
 }
 
 int main() {
+  barrier_init(&barrier, 2);
   int *a = new int(0);
   pthread_t t;
   pthread_create(&t, 0, Thread, a);
-  sleep(1);
+  barrier_wait(&barrier);
   delete a;
   pthread_join(t, 0);
 }
diff --git a/test/tsan/atomic_free2.cc b/test/tsan/atomic_free2.cc
index c50be6bba..4a9f268a4 100644
--- a/test/tsan/atomic_free2.cc
+++ b/test/tsan/atomic_free2.cc
@@ -1,18 +1,19 @@
 // RUN: %clangxx_tsan -O1 %s -o %t && %deflake %run %t | FileCheck %s
-#include <pthread.h>
-#include <unistd.h>
+#include "test.h"
 
 void *Thread(void *a) {
-  sleep(1);
+  barrier_wait(&barrier);
   __atomic_fetch_add((int*)a, 1, __ATOMIC_SEQ_CST);
   return 0;
 }
 
 int main() {
+  barrier_init(&barrier, 2);
   int *a = new int(0);
   pthread_t t;
   pthread_create(&t, 0, Thread, a);
   delete a;
+  barrier_wait(&barrier);
   pthread_join(t, 0);
 }
 
diff --git a/test/tsan/atomic_norace.cc b/test/tsan/atomic_norace.cc
index d9ccda588..625109b1f 100644
--- a/test/tsan/atomic_norace.cc
+++ b/test/tsan/atomic_norace.cc
@@ -1,7 +1,5 @@
 // RUN: %clangxx_tsan -O1 %s -o %t && %run %t 2>&1 | FileCheck %s
-#include <pthread.h>
-#include <stdio.h>
-#include <unistd.h>
+#include "test.h"
 
 const int kTestCount = 4;
 typedef long long T;
@@ -36,7 +34,8 @@ void *Thread(void *p) {
   for (int i = 0; i < kTestCount; i++) {
     Test(i, &atomics[i], false);
   }
-  sleep(2);
+  barrier_wait(&barrier);
+  barrier_wait(&barrier);
   for (int i = 0; i < kTestCount; i++) {
     fprintf(stderr, "Test %d reverse\n", i);
     Test(i, &atomics[kTestCount + i], false);
@@ -45,9 +44,10 @@ void *Thread(void *p) {
 }
 
 int main() {
+  barrier_init(&barrier, 2);
   pthread_t t;
   pthread_create(&t, 0, Thread, 0);
-  sleep(1);
+  barrier_wait(&barrier);
   for (int i = 0; i < kTestCount; i++) {
     fprintf(stderr, "Test %d\n", i);
     Test(i, &atomics[i], true);
@@ -55,6 +55,7 @@ int main() {
   for (int i = 0; i < kTestCount; i++) {
     Test(i, &atomics[kTestCount + i], true);
   }
+  barrier_wait(&barrier);
   pthread_join(t, 0);
 }
 
diff --git a/test/tsan/atomic_race.cc b/test/tsan/atomic_race.cc
index 9cee8ed82..5a0317c4a 100644
--- a/test/tsan/atomic_race.cc
+++ b/test/tsan/atomic_race.cc
@@ -1,7 +1,5 @@
 // RUN: %clangxx_tsan -O1 %s -o %t && %deflake %run %t | FileCheck %s
-#include <pthread.h>
-#include <unistd.h>
-#include <stdio.h>
+#include "test.h"
 
 const int kTestCount = 4;
 typedef long long T;
@@ -36,7 +34,8 @@ void *Thread(void *p) {
   for (int i = 0; i < kTestCount; i++) {
     Test(i, &atomics[i], false);
   }
-  sleep(4);
+  barrier_wait(&barrier);
+  barrier_wait(&barrier);
   for (int i = 0; i < kTestCount; i++) {
     fprintf(stderr, "Test %d reverse\n", i);
     Test(i, &atomics[kTestCount + i], false);
@@ -45,9 +44,10 @@ void *Thread(void *p) {
 }
 
 int main() {
+  barrier_init(&barrier, 2);
   pthread_t t;
   pthread_create(&t, 0, Thread, 0);
-  sleep(1);
+  barrier_wait(&barrier);
   for (int i = 0; i < kTestCount; i++) {
     fprintf(stderr, "Test %d\n", i);
     Test(i, &atomics[i], true);
@@ -55,6 +55,7 @@ int main() {
   for (int i = 0; i < kTestCount; i++) {
     Test(i, &atomics[kTestCount + i], true);
   }
+  barrier_wait(&barrier);
   pthread_join(t, 0);
 }
 
diff --git a/test/tsan/atomic_stack.cc b/test/tsan/atomic_stack.cc
index 7e3176f8e..979eaea8b 100644
--- a/test/tsan/atomic_stack.cc
+++ b/test/tsan/atomic_stack.cc
@@ -1,21 +1,22 @@
 // RUN: %clangxx_tsan -O1 %s -o %t && %deflake %run %t | FileCheck %s
-#include <pthread.h>
-#include <unistd.h>
+#include "test.h"
 
 int Global;
 
 void *Thread1(void *x) {
-  sleep(1);
+  barrier_wait(&barrier);
   __atomic_fetch_add(&Global, 1, __ATOMIC_RELAXED);
   return NULL;
 }
 
 void *Thread2(void *x) {
   Global++;
+  barrier_wait(&barrier);
   return NULL;
 }
 
 int main() {
+  barrier_init(&barrier, 2);
   pthread_t t[2];
   pthread_create(&t[0], NULL, Thread1, NULL);
   pthread_create(&t[1], NULL, Thread2, NULL);
diff --git a/test/tsan/benign_race.cc b/test/tsan/benign_race.cc
index b6cba19aa..2f72fe186 100644
--- a/test/tsan/benign_race.cc
+++ b/test/tsan/benign_race.cc
@@ -1,7 +1,5 @@
 // RUN: %clang_tsan -O1 %s -o %t && %run %t 2>&1 | FileCheck %s
-#include <pthread.h>
-#include <stdio.h>
-#include <unistd.h>
+#include "test.h"
 
 int Global;
 int WTFGlobal;
@@ -18,10 +16,12 @@ void WTFAnnotateBenignRaceSized(const char *f, int l,
 void *Thread(void *x) {
   Global = 42;
   WTFGlobal = 142;
+  barrier_wait(&barrier);
   return 0;
 }
 
 int main() {
+  barrier_init(&barrier, 2);
   AnnotateBenignRaceSized(__FILE__, __LINE__,
                           &Global, sizeof(Global), "Race on Global");
   WTFAnnotateBenignRaceSized(__FILE__, __LINE__,
@@ -29,7 +29,7 @@ int main() {
                              "Race on WTFGlobal");
   pthread_t t;
   pthread_create(&t, 0, Thread, 0);
-  sleep(1);
+  barrier_wait(&barrier);
   Global = 43;
   WTFGlobal = 143;
   pthread_join(t, 0);
diff --git a/test/tsan/blacklist2.cc b/test/tsan/blacklist2.cc
index 1092561e5..629b58821 100644
--- a/test/tsan/blacklist2.cc
+++ b/test/tsan/blacklist2.cc
@@ -5,14 +5,12 @@
 
 // RUN: %clangxx_tsan -O1 %s -fsanitize-blacklist=%t.blacklist -o %t
 // RUN: %deflake %run %t 2>&1 | FileCheck %s
-#include <pthread.h>
-#include <stdio.h>
-#include <unistd.h>
+#include "test.h"
 
 int Global;
 
 void *Thread1(void *x) {
-  sleep(1);
+  barrier_wait(&barrier);
   // CHECK: ThreadSanitizer: data race
   // CHECK: Write of size 4
   // CHECK: #0 Thread1{{.*}}blacklist2.cc:[[@LINE+1]]
@@ -35,10 +33,12 @@ void *Blacklisted_Thread2(void *x) {
   Global--;
   // CHECK: #2 Blacklisted_Thread2{{.*}}blacklist2.cc:[[@LINE+1]]
   CallTouchGlobal();
+  barrier_wait(&barrier);
   return NULL;
 }
 
 int main() {
+  barrier_init(&barrier, 2);
   pthread_t t[2];
   pthread_create(&t[0], NULL, Thread1, NULL);
   pthread_create(&t[1], NULL, Blacklisted_Thread2, NULL);
diff --git a/test/tsan/cond_cancel.c b/test/tsan/cond_cancel.c
index 397cad4b1..e744570b1 100644
--- a/test/tsan/cond_cancel.c
+++ b/test/tsan/cond_cancel.c
@@ -2,10 +2,7 @@
 // CHECK-NOT: WARNING
 // CHECK: OK
 
-#include <stdio.h>
-#include <stdlib.h>
-#include <pthread.h>
-#include <unistd.h>
+#include "test.h"
 
 pthread_mutex_t m;
 pthread_cond_t c;
@@ -14,6 +11,7 @@ int x;
 void *thr1(void *p) {
   pthread_mutex_lock(&m);
   pthread_cleanup_push((void(*)(void *arg))pthread_mutex_unlock, &m);
+  barrier_wait(&barrier);
   while (x == 0)
     pthread_cond_wait(&c, &m);
   pthread_cleanup_pop(1);
@@ -21,12 +19,15 @@ void *thr1(void *p) {
 }
 
 int main() {
+  barrier_init(&barrier, 2);
+
   pthread_t th;
 
   pthread_mutex_init(&m, 0);
   pthread_cond_init(&c, 0);
 
   pthread_create(&th, 0, thr1, 0);
+  barrier_wait(&barrier);
   sleep(1);  // let it block on cond var
   pthread_cancel(th);
 
diff --git a/test/tsan/cond_race.cc b/test/tsan/cond_race.cc
index fa42fafca..52654f16e 100644
--- a/test/tsan/cond_race.cc
+++ b/test/tsan/cond_race.cc
@@ -3,10 +3,7 @@
 // CHECK: ThreadSanitizer: data race
 // CHECK: pthread_cond_signal
 
-#include <stdio.h>
-#include <stdlib.h>
-#include <pthread.h>
-#include <unistd.h>
+#include "test.h"
 
 struct Ctx {
   pthread_mutex_t m;
@@ -20,10 +17,12 @@ void *thr(void *p) {
   c->done = true;
   pthread_mutex_unlock(&c->m);
   pthread_cond_signal(&c->c);
+  barrier_wait(&barrier);
   return 0;
 }
 
 int main() {
+  barrier_init(&barrier, 2);
   Ctx *c = new Ctx();
   pthread_mutex_init(&c->m, 0);
   pthread_cond_init(&c->c, 0);
@@ -33,8 +32,8 @@ int main() {
   while (!c->done)
     pthread_cond_wait(&c->c, &c->m);
   pthread_mutex_unlock(&c->m);
-  // w/o this sleep, it can be reported as use-after-free
-  sleep(1);
+  // otherwise it can be reported as use-after-free
+  barrier_wait(&barrier);
   delete c;
   pthread_join(th, 0);
 }
diff --git a/test/tsan/deadlock_detector_stress_test.cc b/test/tsan/deadlock_detector_stress_test.cc
index 53624782e..e02a9123f 100644
--- a/test/tsan/deadlock_detector_stress_test.cc
+++ b/test/tsan/deadlock_detector_stress_test.cc
@@ -7,12 +7,9 @@
 // RUN: TSAN_OPTIONS=detect_deadlocks=1 %deflake %run %t | FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-RD
 // RUN: %clangxx_tsan %s -o %t -DLockType=PthreadRecursiveMutex
 // RUN: TSAN_OPTIONS=detect_deadlocks=1 %deflake %run %t | FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-REC
-#include <pthread.h>
+#include "test.h"
 #undef NDEBUG
 #include <assert.h>
-#include <stdlib.h>
-#include <stdio.h>
-#include <unistd.h>
 #include <new>
 
 #ifndef LockType
@@ -224,7 +221,7 @@ class LockTest {
     fprintf(stderr, "Starting Test5\n");
     // CHECK: Starting Test5
     Init(5);
-    RunThreads(&LockTest::Lock_0_1, &LockTest::Lock_1_0);
+    RunThreads(&LockTest::Lock_0_1<true>, &LockTest::Lock_1_0<true>);
     // CHECK: WARNING: ThreadSanitizer: lock-order-inversion
     // CHECK: Cycle in lock order graph: [[M1:M[0-9]+]] ({{.*}}) => [[M2:M[0-9]+]] ({{.*}}) => [[M1]]
     // CHECK: Mutex [[M2]] acquired here while holding mutex [[M1]] in thread [[T1:T[0-9]+]]
@@ -503,8 +500,21 @@ class LockTest {
 
  private:
   void Lock2(size_t l1, size_t l2) { L(l1); L(l2); U(l2); U(l1); }
-  void Lock_0_1() { Lock2(0, 1); }
-  void Lock_1_0() { sleep(1); Lock2(1, 0); }
+
+  template<bool wait = false>
+  void Lock_0_1() {
+    Lock2(0, 1);
+    if (wait)
+      barrier_wait(&barrier);
+  }
+
+  template<bool wait = false>
+  void Lock_1_0() {
+    if (wait)
+      barrier_wait(&barrier);
+    Lock2(1, 0);
+  }
+
   void Lock1_Loop(size_t i, size_t n_iter) {
     for (size_t it = 0; it < n_iter; it++) {
       // if ((it & (it - 1)) == 0) fprintf(stderr, "%zd", i);
@@ -569,6 +579,7 @@ class LockTest {
 };
 
 int main(int argc, char **argv) {
+  barrier_init(&barrier, 2);
   if (argc > 1)
     test_number = atoi(argv[1]);
   if (argc > 2)
diff --git a/test/tsan/deep_stack1.cc b/test/tsan/deep_stack1.cc
index 1d00a0e85..39185efee 100644
--- a/test/tsan/deep_stack1.cc
+++ b/test/tsan/deep_stack1.cc
@@ -1,8 +1,6 @@
 // RUN: %clangxx_tsan -O1 %s -o %t -DORDER1 && %deflake %run %t | FileCheck %s
 // RUN: %clangxx_tsan -O1 %s -o %t -DORDER2 && %deflake %run %t | FileCheck %s
-#include <pthread.h>
-#include <stdio.h>
-#include <unistd.h>
+#include "test.h"
 
 volatile int X;
 volatile int N;
@@ -17,13 +15,17 @@ static void foo() {
 
 void *Thread(void *p) {
 #ifdef ORDER1
-  sleep(1);
+  barrier_wait(&barrier);
 #endif
   F();
+#ifdef ORDER2
+  barrier_wait(&barrier);
+#endif
   return 0;
 }
 
 int main() {
+  barrier_init(&barrier, 2);
   N = 50000;
   F = foo;
   pthread_t t;
@@ -32,9 +34,13 @@ int main() {
   pthread_attr_setstacksize(&a, N * 256 + (1 << 20));
   pthread_create(&t, &a, Thread, 0);
 #ifdef ORDER2
-  sleep(1);
+  barrier_wait(&barrier);
 #endif
   X = 43;
+#ifdef ORDER1
+  barrier_wait(&barrier);
+#endif
+
   pthread_join(t, 0);
 }
 
diff --git a/test/tsan/fd_close_norace.cc b/test/tsan/fd_close_norace.cc
index 7238d64b4..1b52c20f9 100644
--- a/test/tsan/fd_close_norace.cc
+++ b/test/tsan/fd_close_norace.cc
@@ -1,7 +1,5 @@
 // RUN: %clangxx_tsan -O1 %s -o %t && %run %t 2>&1 | FileCheck %s
-#include <pthread.h>
-#include <stdio.h>
-#include <unistd.h>
+#include "test.h"
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <fcntl.h>
@@ -9,17 +7,19 @@
 void *Thread1(void *x) {
   int f = open("/dev/random", O_RDONLY);
   close(f);
+  barrier_wait(&barrier);
   return NULL;
 }
 
 void *Thread2(void *x) {
-  sleep(1);
+  barrier_wait(&barrier);
   int f = open("/dev/random", O_RDONLY);
   close(f);
   return NULL;
 }
 
 int main() {
+  barrier_init(&barrier, 2);
   pthread_t t[2];
   pthread_create(&t[0], NULL, Thread1, NULL);
   pthread_create(&t[1], NULL, Thread2, NULL);
diff --git a/test/tsan/fd_location.cc b/test/tsan/fd_location.cc
index 535329e06..1861c89cb 100644
--- a/test/tsan/fd_location.cc
+++ b/test/tsan/fd_location.cc
@@ -1,23 +1,23 @@
 // RUN: %clangxx_tsan -O1 %s -o %t && %deflake %run %t | FileCheck %s
-#include <pthread.h>
-#include <stdio.h>
-#include <unistd.h>
+#include "test.h"
 
 int fds[2];
 
 void *Thread1(void *x) {
   write(fds[1], "a", 1);
+  barrier_wait(&barrier);
   return NULL;
 }
 
 void *Thread2(void *x) {
-  sleep(1);
+  barrier_wait(&barrier);
   close(fds[0]);
   close(fds[1]);
   return NULL;
 }
 
 int main() {
+  barrier_init(&barrier, 2);
   pipe(fds);
   pthread_t t[2];
   pthread_create(&t[0], NULL, Thread1, NULL);
diff --git a/test/tsan/fd_pipe_race.cc b/test/tsan/fd_pipe_race.cc
index 88c4ed4aa..b94893b93 100644
--- a/test/tsan/fd_pipe_race.cc
+++ b/test/tsan/fd_pipe_race.cc
@@ -1,23 +1,23 @@
 // RUN: %clangxx_tsan -O1 %s -o %t && %deflake %run %t | FileCheck %s
-#include <pthread.h>
-#include <stdio.h>
-#include <unistd.h>
+#include "test.h"
 
 int fds[2];
 
 void *Thread1(void *x) {
   write(fds[1], "a", 1);
+  barrier_wait(&barrier);
   return NULL;
 }
 
 void *Thread2(void *x) {
-  sleep(1);
+  barrier_wait(&barrier);
   close(fds[0]);
   close(fds[1]);
   return NULL;
 }
 
 int main() {
+  barrier_init(&barrier, 2);
   pipe(fds);
   pthread_t t[2];
   pthread_create(&t[0], NULL, Thread1, NULL);
diff --git a/test/tsan/fd_stdout_race.cc b/test/tsan/fd_stdout_race.cc
index d6a2c7c79..fcf8c2130 100644
--- a/test/tsan/fd_stdout_race.cc
+++ b/test/tsan/fd_stdout_race.cc
@@ -1,7 +1,5 @@
 // RUN: %clangxx_tsan -O1 %s -o %t && %deflake %run %t | FileCheck %s
-#include <pthread.h>
-#include <stdio.h>
-#include <unistd.h>
+#include "test.h"
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <fcntl.h>
@@ -9,7 +7,7 @@
 int X;
 
 void *Thread1(void *x) {
-  sleep(1);
+  barrier_wait(&barrier);
   int f = open("/dev/random", O_RDONLY);
   char buf;
   read(f, &buf, 1);
@@ -21,10 +19,12 @@ void *Thread1(void *x) {
 void *Thread2(void *x) {
   X = 43;
   write(STDOUT_FILENO, "a", 1);
+  barrier_wait(&barrier);
   return NULL;
 }
 
 int main() {
+  barrier_init(&barrier, 2);
   pthread_t t[2];
   pthread_create(&t[0], NULL, Thread1, NULL);
   pthread_create(&t[1], NULL, Thread2, NULL);
diff --git a/test/tsan/fork_deadlock.cc b/test/tsan/fork_deadlock.cc
index cc5b12214..9418800bd 100644
--- a/test/tsan/fork_deadlock.cc
+++ b/test/tsan/fork_deadlock.cc
@@ -1,9 +1,6 @@
 // RUN: %clangxx_tsan -O1 %s -o %t && TSAN_OPTIONS="atexit_sleep_ms=50" %run %t 2>&1 | FileCheck %s
-#include <stdlib.h>
-#include <stdio.h>
+#include "test.h"
 #include <errno.h>
-#include <pthread.h>
-#include <unistd.h>
 #include <sys/types.h>
 #include <sys/wait.h>
 
@@ -16,13 +13,14 @@ static void *incrementer(void *p) {
 }
 
 static void *watchdog(void *p) {
-  sleep(100);
+  sleep(100);  // is not intended to exit
   fprintf(stderr, "timed out after 100 seconds\n");
   exit(1);
   return 0;
 }
 
 int main() {
+  barrier_init(&barrier, 2);
   pthread_t th1, th2;
   pthread_create(&th1, 0, incrementer, 0);
   pthread_create(&th2, 0, watchdog, 0);
diff --git a/test/tsan/fork_multithreaded.cc b/test/tsan/fork_multithreaded.cc
index 5176a14d6..3ddb417c7 100644
--- a/test/tsan/fork_multithreaded.cc
+++ b/test/tsan/fork_multithreaded.cc
@@ -1,19 +1,21 @@
 // RUN: %clangxx_tsan -O1 %s -o %t && %run %t 2>&1 | FileCheck %s -check-prefix=CHECK-DIE
 // RUN: %clangxx_tsan -O1 %s -o %t && TSAN_OPTIONS="die_after_fork=0" %run %t 2>&1 | FileCheck %s -check-prefix=CHECK-NODIE
-#include <stdlib.h>
-#include <stdio.h>
+#include "test.h"
 #include <errno.h>
-#include <pthread.h>
-#include <unistd.h>
 #include <sys/types.h>
 #include <sys/wait.h>
 
 static void *sleeper(void *p) {
-  sleep(10);
+  sleep(10);  // not intended to exit during test
+  return 0;
+}
+
+static void *nop(void *p) {
   return 0;
 }
 
 int main() {
+  barrier_init(&barrier, 2);
   pthread_t th;
   pthread_create(&th, 0, sleeper, 0);
   switch (fork()) {
@@ -23,7 +25,7 @@ int main() {
   case 0:  // child
     {
       pthread_t th2;
-      pthread_create(&th2, 0, sleeper, 0);
+      pthread_create(&th2, 0, nop, 0);
       exit(0);
       break;
     }
diff --git a/test/tsan/free_race.c b/test/tsan/free_race.c
index 0fcfa4e90..63cee8c4a 100644
--- a/test/tsan/free_race.c
+++ b/test/tsan/free_race.c
@@ -2,11 +2,7 @@
 // RUN: %deflake %run %t | FileCheck %s --check-prefix=CHECK-NOZUPP
 // RUN: TSAN_OPTIONS="suppressions='%s.supp' print_suppressions=1" %run %t 2>&1 | FileCheck %s --check-prefix=CHECK-SUPP
 
-#include <pthread.h>
-#include <stdlib.h>
-#include <stdio.h>
-#include <stddef.h>
-#include <unistd.h>
+#include "test.h"
 
 int *mem;
 pthread_mutex_t mtx;
@@ -15,11 +11,12 @@ void *Thread1(void *x) {
   pthread_mutex_lock(&mtx);
   free(mem);
   pthread_mutex_unlock(&mtx);
+  barrier_wait(&barrier);
   return NULL;
 }
 
 void *Thread2(void *x) {
-  sleep(1);
+  barrier_wait(&barrier);
   pthread_mutex_lock(&mtx);
   mem[0] = 42;
   pthread_mutex_unlock(&mtx);
@@ -27,6 +24,7 @@ void *Thread2(void *x) {
 }
 
 int main() {
+  barrier_init(&barrier, 2);
   mem = (int*)malloc(100);
   pthread_mutex_init(&mtx, 0);
   pthread_t t;
diff --git a/test/tsan/global_race.cc b/test/tsan/global_race.cc
index e12bb1d22..d70bee4a5 100644
--- a/test/tsan/global_race.cc
+++ b/test/tsan/global_race.cc
@@ -1,24 +1,23 @@
 // RUN: %clangxx_tsan -O1 %s -o %T/global_race.cc.exe && %deflake %run %T/global_race.cc.exe | FileCheck %s
-#include <pthread.h>
-#include <stdio.h>
-#include <stddef.h>
-#include <unistd.h>
+#include "test.h"
 
 int GlobalData[10];
 
 void *Thread(void *a) {
-  sleep(1);
+  barrier_wait(&barrier);
   GlobalData[2] = 42;
   return 0;
 }
 
 int main() {
+  barrier_init(&barrier, 2);
   // On FreeBSD, the %p conversion specifier works as 0x%x and thus does not
   // match to the format used in the diagnotic message.
   fprintf(stderr, "addr=0x%012lx\n", (unsigned long) GlobalData);
   pthread_t t;
   pthread_create(&t, 0, Thread, 0);
   GlobalData[2] = 43;
+  barrier_wait(&barrier);
   pthread_join(t, 0);
 }
 
diff --git a/test/tsan/global_race2.cc b/test/tsan/global_race2.cc
index ac994cc0f..6631008d8 100644
--- a/test/tsan/global_race2.cc
+++ b/test/tsan/global_race2.cc
@@ -1,24 +1,23 @@
 // RUN: %clangxx_tsan -O1 %s -o %t && %deflake %run %t | FileCheck %s
-#include <pthread.h>
-#include <stdio.h>
-#include <stddef.h>
-#include <unistd.h>
+#include "test.h"
 
 int x;
 
 void *Thread(void *a) {
-  sleep(1);
+  barrier_wait(&barrier);
   x = 1;
   return 0;
 }
 
 int main() {
+  barrier_init(&barrier, 2);
   // On FreeBSD, the %p conversion specifier works as 0x%x and thus does not
   // match to the format used in the diagnotic message.
   fprintf(stderr, "addr2=0x%012lx\n", (unsigned long) &x);
   pthread_t t;
   pthread_create(&t, 0, Thread, 0);
   x = 0;
+  barrier_wait(&barrier);
   pthread_join(t, 0);
 }
 
diff --git a/test/tsan/global_race3.cc b/test/tsan/global_race3.cc
index a3222bb3d..e7e9a7fef 100644
--- a/test/tsan/global_race3.cc
+++ b/test/tsan/global_race3.cc
@@ -1,8 +1,5 @@
 // RUN: %clangxx_tsan -O1 %s -o %t && %deflake %run %t | FileCheck %s
-#include <pthread.h>
-#include <stdio.h>
-#include <stddef.h>
-#include <unistd.h>
+#include "test.h"
 
 namespace XXX {
   struct YYY {
@@ -12,18 +9,20 @@ namespace XXX {
 }
 
 void *Thread(void *a) {
-  sleep(1);
+  barrier_wait(&barrier);
   XXX::YYY::ZZZ[0] = 1;
   return 0;
 }
 
 int main() {
+  barrier_init(&barrier, 2);
   // On FreeBSD, the %p conversion specifier works as 0x%x and thus does not
   // match to the format used in the diagnotic message.
   fprintf(stderr, "addr3=0x%012lx\n", (unsigned long) XXX::YYY::ZZZ);
   pthread_t t;
   pthread_create(&t, 0, Thread, 0);
   XXX::YYY::ZZZ[0] = 0;
+  barrier_wait(&barrier);
   pthread_join(t, 0);
 }
 
diff --git a/test/tsan/halt_on_error.cc b/test/tsan/halt_on_error.cc
index 3c55c60a4..e55454b57 100644
--- a/test/tsan/halt_on_error.cc
+++ b/test/tsan/halt_on_error.cc
@@ -1,21 +1,21 @@
 // RUN: %clang_tsan -O1 %s -o %t && TSAN_OPTIONS="$TSAN_OPTIONS halt_on_error=1" %deflake %run %t | FileCheck %s
-#include <pthread.h>
-#include <stdio.h>
-#include <unistd.h>
+#include "test.h"
 
 int X;
 
 void *Thread(void *x) {
-  sleep(1);
+  barrier_wait(&barrier);
   X = 42;
   return 0;
 }
 
 int main() {
+  barrier_init(&barrier, 2);
   fprintf(stderr, "BEFORE\n");
   pthread_t t;
   pthread_create(&t, 0, Thread, 0);
   X = 43;
+  barrier_wait(&barrier);
   pthread_join(t, 0);
   fprintf(stderr, "AFTER\n");
   return 0;
diff --git a/test/tsan/ignore_free.cc b/test/tsan/ignore_free.cc
index 1df6dce2f..bb6c6ee14 100644
--- a/test/tsan/ignore_free.cc
+++ b/test/tsan/ignore_free.cc
@@ -1,8 +1,5 @@
 // RUN: %clang_tsan -O1 %s -o %t && %run %t 2>&1 | FileCheck %s
-#include <pthread.h>
-#include <stdlib.h>
-#include <stdio.h>
-#include <unistd.h>
+#include "test.h"
 
 extern "C" {
 void AnnotateIgnoreReadsBegin(const char *f, int l);
@@ -13,14 +10,16 @@ void AnnotateIgnoreWritesEnd(const char *f, int l);
 
 void *Thread(void *p) {
   *(int*)p = 42;
+  barrier_wait(&barrier);
   return 0;
 }
 
 int main() {
+  barrier_init(&barrier, 2);
   int *p = new int(0);
   pthread_t t;
   pthread_create(&t, 0, Thread, p);
-  sleep(1);
+  barrier_wait(&barrier);
   AnnotateIgnoreReadsBegin(__FILE__, __LINE__);
   AnnotateIgnoreWritesBegin(__FILE__, __LINE__);
   free(p);
diff --git a/test/tsan/ignore_malloc.cc b/test/tsan/ignore_malloc.cc
index 0f1fb5e3d..1f633f062 100644
--- a/test/tsan/ignore_malloc.cc
+++ b/test/tsan/ignore_malloc.cc
@@ -1,8 +1,5 @@
 // RUN: %clang_tsan -O1 %s -o %t && %run %t 2>&1 | FileCheck %s
-#include <pthread.h>
-#include <stdlib.h>
-#include <stdio.h>
-#include <unistd.h>
+#include "test.h"
 
 extern "C" {
 void AnnotateIgnoreReadsBegin(const char *f, int l);
@@ -16,7 +13,7 @@ int *g;
 void *Thread(void *a) {
   int *p = 0;
   while ((p = __atomic_load_n(&g, __ATOMIC_RELAXED)) == 0)
-    usleep(100);
+    usleep(100);  // spin-wait
   *p = 42;
   return 0;
 }
diff --git a/test/tsan/ignore_race.cc b/test/tsan/ignore_race.cc
index c6e067fab..cc33b66b2 100644
--- a/test/tsan/ignore_race.cc
+++ b/test/tsan/ignore_race.cc
@@ -1,7 +1,5 @@
 // RUN: %clang_tsan -O1 %s -o %t && %run %t 2>&1 | FileCheck %s
-#include <pthread.h>
-#include <stdio.h>
-#include <unistd.h>
+#include "test.h"
 
 int Global;
 
@@ -16,13 +14,15 @@ void *Thread(void *x) {
   Global = 42;
   AnnotateIgnoreReadsEnd(__FILE__, __LINE__);
   AnnotateIgnoreWritesEnd(__FILE__, __LINE__);
+  barrier_wait(&barrier);
   return 0;
 }
 
 int main() {
+  barrier_init(&barrier, 2);
   pthread_t t;
   pthread_create(&t, 0, Thread, 0);
-  sleep(1);
+  barrier_wait(&barrier);
   Global = 43;
   pthread_join(t, 0);
   printf("OK\n");
diff --git a/test/tsan/inlined_memcpy_race.cc b/test/tsan/inlined_memcpy_race.cc
index a95576a83..e3ed07abc 100644
--- a/test/tsan/inlined_memcpy_race.cc
+++ b/test/tsan/inlined_memcpy_race.cc
@@ -1,24 +1,23 @@
 // RUN: %clangxx_tsan -O1 %s -o %t && %deflake %run %t | FileCheck %s
-#include <pthread.h>
-#include <stddef.h>
-#include <stdio.h>
+#include "test.h"
 #include <string.h>
-#include <unistd.h>
 
 int x[4], z[4];
 
 void *MemCpyThread(void *a) {
   memcpy((int*)a, z, 16);
+  barrier_wait(&barrier);
   return NULL;
 }
 
 void *MemSetThread(void *a) {
-  sleep(1);
+  barrier_wait(&barrier);
   memset((int*)a, 0, 16);
   return NULL;
 }
 
 int main() {
+  barrier_init(&barrier, 2);
   pthread_t t[2];
   // Race on x between memcpy and memset
   pthread_create(&t[0], NULL, MemCpyThread, x);
diff --git a/test/tsan/inlined_memcpy_race2.cc b/test/tsan/inlined_memcpy_race2.cc
index 63b560f02..37414ba5d 100644
--- a/test/tsan/inlined_memcpy_race2.cc
+++ b/test/tsan/inlined_memcpy_race2.cc
@@ -1,24 +1,23 @@
 // RUN: %clangxx_tsan -O1 %s -o %t && %deflake %run %t | FileCheck %s
-#include <pthread.h>
-#include <stddef.h>
-#include <stdio.h>
+#include "test.h"
 #include <string.h>
-#include <unistd.h>
 
 int y[4], z[4];
 
 void *MemMoveThread(void *a) {
   memmove((int*)a, z, 16);
+  barrier_wait(&barrier);
   return NULL;
 }
 
 void *MemSetThread(void *a) {
-  sleep(1);
+  barrier_wait(&barrier);
   memset((int*)a, 0, 16);
   return NULL;
 }
 
 int main() {
+  barrier_init(&barrier, 2);
   pthread_t t[2];
   // Race on y between memmove and memset
   pthread_create(&t[0], NULL, MemMoveThread, y);
diff --git a/test/tsan/java.h b/test/tsan/java.h
index 66f46239a..35fdbc1e7 100644
--- a/test/tsan/java.h
+++ b/test/tsan/java.h
@@ -1,7 +1,4 @@
-#include <pthread.h>
-#include <stdlib.h>
-#include <stdio.h>
-#include <unistd.h>
+#include "test.h"
 
 extern "C" {
 typedef unsigned long jptr;  // NOLINT
diff --git a/test/tsan/java_finalizer.cc b/test/tsan/java_finalizer.cc
index d5c6a22d1..acbbf08ad 100644
--- a/test/tsan/java_finalizer.cc
+++ b/test/tsan/java_finalizer.cc
@@ -2,13 +2,14 @@
 #include "java.h"
 
 void *Thread(void *p) {
-  sleep(1);
+  barrier_wait(&barrier);
   __tsan_java_finalize();
   *(int*)p = 42;
   return 0;
 }
 
 int main() {
+  barrier_init(&barrier, 2);
   int const kHeapSize = 1024 * 1024;
   jptr jheap = (jptr)malloc(kHeapSize + 8) + 8;
   __tsan_java_init(jheap, kHeapSize);
@@ -17,6 +18,7 @@ int main() {
   pthread_t th;
   pthread_create(&th, 0, Thread, (void*)jheap);
   *(int*)jheap = 43;
+  barrier_wait(&barrier);
   pthread_join(th, 0);
   __tsan_java_free(jheap, kBlockSize);
   fprintf(stderr, "DONE\n");
diff --git a/test/tsan/java_lock.cc b/test/tsan/java_lock.cc
index 36a0f8b7b..f17205295 100644
--- a/test/tsan/java_lock.cc
+++ b/test/tsan/java_lock.cc
@@ -1,12 +1,11 @@
 // RUN: %clangxx_tsan -O1 %s -o %t && %run %t 2>&1 | FileCheck %s
 #include "java.h"
-#include <unistd.h>
 
 jptr varaddr;
 jptr lockaddr;
 
 void *Thread(void *p) {
-  sleep(1);
+  barrier_wait(&barrier);
   __tsan_java_mutex_lock(lockaddr);
   *(int*)varaddr = 42;
   __tsan_java_mutex_unlock(lockaddr);
@@ -14,6 +13,7 @@ void *Thread(void *p) {
 }
 
 int main() {
+  barrier_init(&barrier, 2);
   int const kHeapSize = 1024 * 1024;
   jptr jheap = (jptr)malloc(kHeapSize + 8) + 8;
   __tsan_java_init(jheap, kHeapSize);
@@ -26,6 +26,7 @@ int main() {
   __tsan_java_mutex_lock(lockaddr);
   *(int*)varaddr = 43;
   __tsan_java_mutex_unlock(lockaddr);
+  barrier_wait(&barrier);
   pthread_join(th, 0);
   __tsan_java_free(jheap, kBlockSize);
   fprintf(stderr, "DONE\n");
diff --git a/test/tsan/java_lock_move.cc b/test/tsan/java_lock_move.cc
index 19c3e35d6..fe5491dc2 100644
--- a/test/tsan/java_lock_move.cc
+++ b/test/tsan/java_lock_move.cc
@@ -7,7 +7,7 @@ jptr varaddr2;
 jptr lockaddr2;
 
 void *Thread(void *p) {
-  sleep(1);
+  barrier_wait(&barrier);
   __tsan_java_mutex_lock(lockaddr2);
   *(int*)varaddr2 = 42;
   __tsan_java_mutex_unlock(lockaddr2);
@@ -15,6 +15,7 @@ void *Thread(void *p) {
 }
 
 int main() {
+  barrier_init(&barrier, 2);
   int const kHeapSize = 1024 * 1024;
   jptr jheap = (jptr)malloc(kHeapSize + 8) + 8;
   __tsan_java_init(jheap, kHeapSize);
@@ -31,6 +32,7 @@ int main() {
   *(int*)varaddr = 43;
   __tsan_java_mutex_unlock(lockaddr);
   __tsan_java_move(varaddr, varaddr2, kBlockSize);
+  barrier_wait(&barrier);
   pthread_join(th, 0);
   __tsan_java_free(varaddr2, kBlockSize);
   printf("DONE\n");
diff --git a/test/tsan/java_lock_rec.cc b/test/tsan/java_lock_rec.cc
index 2b0ab0eb9..f0bf40196 100644
--- a/test/tsan/java_lock_rec.cc
+++ b/test/tsan/java_lock_rec.cc
@@ -1,6 +1,5 @@
 // RUN: %clangxx_tsan -O1 %s -o %t && %run %t 2>&1 | FileCheck %s
 #include "java.h"
-#include <unistd.h>
 
 jptr varaddr;
 jptr lockaddr;
@@ -14,7 +13,8 @@ void *Thread(void *p) {
     printf("FAILED 0 rec=%d\n", rec);
     exit(1);
   }
-  sleep(2);
+  barrier_wait(&barrier);
+  barrier_wait(&barrier);
   __tsan_java_mutex_lock_rec(lockaddr, rec);
   if (*(int*)varaddr != 43) {
     printf("FAILED 3 var=%d\n", *(int*)varaddr);
@@ -26,6 +26,7 @@ void *Thread(void *p) {
 }
 
 int main() {
+  barrier_init(&barrier, 2);
   int const kHeapSize = 1024 * 1024;
   jptr jheap = (jptr)malloc(kHeapSize + 8) + 8;
   __tsan_java_init(jheap, kHeapSize);
@@ -36,7 +37,7 @@ int main() {
   lockaddr = jheap + 8;
   pthread_t th;
   pthread_create(&th, 0, Thread, 0);
-  sleep(1);
+  barrier_wait(&barrier);
   __tsan_java_mutex_lock(lockaddr);
   if (*(int*)varaddr != 42) {
     printf("FAILED 1 var=%d\n", *(int*)varaddr);
@@ -44,6 +45,7 @@ int main() {
   }
   *(int*)varaddr = 43;
   __tsan_java_mutex_unlock(lockaddr);
+  barrier_wait(&barrier);
   pthread_join(th, 0);
   __tsan_java_free(jheap, kBlockSize);
   printf("DONE\n");
diff --git a/test/tsan/java_lock_rec_race.cc b/test/tsan/java_lock_rec_race.cc
index 841aa3963..3da8ad076 100644
--- a/test/tsan/java_lock_rec_race.cc
+++ b/test/tsan/java_lock_rec_race.cc
@@ -1,6 +1,5 @@
 // RUN: %clangxx_tsan -O1 %s -o %t && %deflake %run %t | FileCheck %s
 #include "java.h"
-#include <unistd.h>
 
 jptr varaddr;
 jptr lockaddr;
@@ -15,7 +14,8 @@ void *Thread(void *p) {
     exit(1);
   }
   *(int*)varaddr = 42;
-  sleep(2);
+  barrier_wait(&barrier);
+  barrier_wait(&barrier);
   __tsan_java_mutex_lock_rec(lockaddr, rec);
   __tsan_java_mutex_unlock(lockaddr);
   __tsan_java_mutex_unlock(lockaddr);
@@ -24,6 +24,7 @@ void *Thread(void *p) {
 }
 
 int main() {
+  barrier_init(&barrier, 2);
   int const kHeapSize = 1024 * 1024;
   jptr jheap = (jptr)malloc(kHeapSize + 8) + 8;
   __tsan_java_init(jheap, kHeapSize);
@@ -34,10 +35,11 @@ int main() {
   lockaddr = jheap + 8;
   pthread_t th;
   pthread_create(&th, 0, Thread, 0);
-  sleep(1);
+  barrier_wait(&barrier);
   __tsan_java_mutex_lock(lockaddr);
   *(int*)varaddr = 43;
   __tsan_java_mutex_unlock(lockaddr);
+  barrier_wait(&barrier);
   pthread_join(th, 0);
   __tsan_java_free(jheap, kBlockSize);
   printf("DONE\n");
diff --git a/test/tsan/java_move_overlap.cc b/test/tsan/java_move_overlap.cc
index 12955b4ba..7ed98ef1a 100644
--- a/test/tsan/java_move_overlap.cc
+++ b/test/tsan/java_move_overlap.cc
@@ -13,7 +13,7 @@ jptr lockaddr1_new;
 jptr lockaddr2_new;
 
 void *Thread(void *p) {
-  sleep(1);
+  barrier_wait(&barrier);
   __tsan_java_mutex_lock(lockaddr1_new);
   *(char*)varaddr1_new = 43;
   __tsan_java_mutex_unlock(lockaddr1_new);
@@ -24,6 +24,7 @@ void *Thread(void *p) {
 }
 
 int main(int argc, char **argv) {
+  barrier_init(&barrier, 2);
   int const kHeapSize = 1024 * 1024;
   void *jheap = malloc(kHeapSize);
   jheap = (char*)jheap + 8;
@@ -62,6 +63,7 @@ int main(int argc, char **argv) {
   __tsan_java_mutex_unlock(lockaddr2_old);
 
   __tsan_java_move(varaddr1_old, varaddr1_new, kBlockSize);
+  barrier_wait(&barrier);
   pthread_join(th, 0);
   __tsan_java_free(varaddr1_new, kBlockSize);
   printf("DONE\n");
diff --git a/test/tsan/java_move_overlap_race.cc b/test/tsan/java_move_overlap_race.cc
index 2b3769be6..874b90b26 100644
--- a/test/tsan/java_move_overlap_race.cc
+++ b/test/tsan/java_move_overlap_race.cc
@@ -9,13 +9,14 @@ jptr varaddr1_new;
 jptr varaddr2_new;
 
 void *Thread(void *p) {
-  sleep(1);
+  barrier_wait(&barrier);
   *(int*)varaddr1_new = 43;
   *(int*)varaddr2_new = 43;
   return 0;
 }
 
 int main(int argc, char **argv) {
+  barrier_init(&barrier, 2);
   int const kHeapSize = 1024 * 1024;
   void *jheap = malloc(kHeapSize);
   jheap = (char*)jheap + 8;
@@ -42,6 +43,7 @@ int main(int argc, char **argv) {
   *(int*)varaddr2_old = 43;
 
   __tsan_java_move(varaddr1_old, varaddr1_new, kBlockSize);
+  barrier_wait(&barrier);
   pthread_join(th, 0);
   __tsan_java_free(varaddr1_new, kBlockSize);
   printf("DONE\n");
diff --git a/test/tsan/java_race_move.cc b/test/tsan/java_race_move.cc
index 8a51be92a..6d1b09216 100644
--- a/test/tsan/java_race_move.cc
+++ b/test/tsan/java_race_move.cc
@@ -5,12 +5,13 @@ jptr varaddr;
 jptr varaddr2;
 
 void *Thread(void *p) {
-  sleep(1);
+  barrier_wait(&barrier);
   *(int*)varaddr2 = 42;
   return 0;
 }
 
 int main() {
+  barrier_init(&barrier, 2);
   int const kHeapSize = 1024 * 1024;
   jptr jheap = (jptr)malloc(kHeapSize + 8) + 8;
   __tsan_java_init(jheap, kHeapSize);
@@ -23,6 +24,7 @@ int main() {
   pthread_create(&th, 0, Thread, 0);
   *(int*)varaddr = 43;
   __tsan_java_move(varaddr, varaddr2, kBlockSize);
+  barrier_wait(&barrier);
   pthread_join(th, 0);
   __tsan_java_free(varaddr2, kBlockSize);
   fprintf(stderr, "DONE\n");
diff --git a/test/tsan/java_rwlock.cc b/test/tsan/java_rwlock.cc
index b03afa6e0..a4cc92a13 100644
--- a/test/tsan/java_rwlock.cc
+++ b/test/tsan/java_rwlock.cc
@@ -1,12 +1,11 @@
 // RUN: %clangxx_tsan -O1 %s -o %t && %run %t 2>&1 | FileCheck %s
 #include "java.h"
-#include <unistd.h>
 
 jptr varaddr;
 jptr lockaddr;
 
 void *Thread(void *p) {
-  sleep(1);
+  barrier_wait(&barrier);
   __tsan_java_mutex_read_lock(lockaddr);
   *(int*)varaddr = 42;
   __tsan_java_mutex_read_unlock(lockaddr);
@@ -14,6 +13,7 @@ void *Thread(void *p) {
 }
 
 int main() {
+  barrier_init(&barrier, 2);
   int const kHeapSize = 1024 * 1024;
   jptr jheap = (jptr)malloc(kHeapSize + 8) + 8;
   __tsan_java_init(jheap, kHeapSize);
@@ -26,6 +26,7 @@ int main() {
   __tsan_java_mutex_lock(lockaddr);
   *(int*)varaddr = 43;
   __tsan_java_mutex_unlock(lockaddr);
+  barrier_wait(&barrier);
   pthread_join(th, 0);
   __tsan_java_free(jheap, kBlockSize);
   printf("DONE\n");
diff --git a/test/tsan/java_volatile.cc b/test/tsan/java_volatile.cc
index 56f4c2dd4..885b4f241 100644
--- a/test/tsan/java_volatile.cc
+++ b/test/tsan/java_volatile.cc
@@ -1,19 +1,19 @@
 // RUN: %clangxx_tsan -O1 %s -o %t && %run %t 2>&1 | FileCheck %s
 #include "java.h"
-#include <unistd.h>
 
 jptr varaddr;
 jptr lockaddr;
 
 void *Thread(void *p) {
   while (__atomic_load_n((int*)lockaddr, __ATOMIC_RELAXED) == 0)
-    usleep(1000);
+    usleep(1000);  // spin-wait
   __tsan_java_acquire(lockaddr);
   *(int*)varaddr = 42;
   return 0;
 }
 
 int main() {
+  barrier_init(&barrier, 2);
   int const kHeapSize = 1024 * 1024;
   jptr jheap = (jptr)malloc(kHeapSize + 8) + 8;
   __tsan_java_init(jheap, kHeapSize);
diff --git a/test/tsan/load_shared_lib.cc b/test/tsan/load_shared_lib.cc
index a27dc1cc6..b7934b82d 100644
--- a/test/tsan/load_shared_lib.cc
+++ b/test/tsan/load_shared_lib.cc
@@ -7,35 +7,39 @@
 
 #ifdef BUILD_SO
 
-#include <stddef.h>
-#include <unistd.h>
+#include "test.h"
 
 int GLOB_SHARED = 0;
 
 extern "C"
+void init_so() {
+  barrier_init(&barrier, 2);
+}
+
+extern "C"
 void *write_from_so(void *unused) {
-  if (unused)
-    sleep(1);
+  if (unused == 0)
+    barrier_wait(&barrier);
   GLOB_SHARED++;
+  if (unused != 0)
+    barrier_wait(&barrier);
   return NULL;
 }
 
 #else  // BUILD_SO
 
+#include "test.h"
 #include <dlfcn.h>
-#include <pthread.h>
-#include <stdio.h>
-#include <stddef.h>
-#include <unistd.h>
-
 #include <string>
 
 int GLOB = 0;
 
 void *write_glob(void *unused) {
-  if (unused)
-    sleep(1);
+  if (unused == 0)
+    barrier_wait(&barrier);
   GLOB++;
+  if (unused != 0)
+    barrier_wait(&barrier);
   return NULL;
 }
 
@@ -48,6 +52,7 @@ void race_two_threads(void *(*access_callback)(void *unused)) {
 }
 
 int main(int argc, char *argv[]) {
+  barrier_init(&barrier, 2);
   std::string path = std::string(argv[0]) + std::string("-so.so");
   race_two_threads(write_glob);
   // CHECK: write_glob
@@ -56,6 +61,9 @@ int main(int argc, char *argv[]) {
     printf("error in dlopen(): %s\n", dlerror());
     return 1;
   }
+  void (*init_so)();
+  *(void **)&init_so = dlsym(lib, "init_so");
+  init_so();
   void *(*write_from_so)(void *unused);
   *(void **)&write_from_so = dlsym(lib, "write_from_so");
   race_two_threads(write_from_so);
diff --git a/test/tsan/malloc_stack.cc b/test/tsan/malloc_stack.cc
index 602736075..ba1d62bcd 100644
--- a/test/tsan/malloc_stack.cc
+++ b/test/tsan/malloc_stack.cc
@@ -1,20 +1,21 @@
 // RUN: %clang_tsan -O1 %s -o %t && %deflake %run %t | FileCheck %s
-#include <pthread.h>
-#include <unistd.h>
+#include "test.h"
 
 _Atomic(int*) p;
 
 void *thr(void *a) {
-  sleep(1);
+  barrier_wait(&barrier);
   int *pp = __c11_atomic_load(&p, __ATOMIC_RELAXED);
   *pp = 42;
   return 0;
 }
 
 int main() {
+  barrier_init(&barrier, 2);
   pthread_t th;
   pthread_create(&th, 0, thr, p);
   __c11_atomic_store(&p, new int, __ATOMIC_RELAXED);
+  barrier_wait(&barrier);
   pthread_join(th, 0);
 }
 
diff --git a/test/tsan/map32bit.cc b/test/tsan/map32bit.cc
index 3a76fa2f6..9dae6880e 100644
--- a/test/tsan/map32bit.cc
+++ b/test/tsan/map32bit.cc
@@ -1,9 +1,6 @@
 // RUN: %clangxx_tsan -O1 %s -o %t && %deflake %run %t 2>&1 | FileCheck %s
-#include <pthread.h>
-#include <stdio.h>
-#include <stddef.h>
+#include "test.h"
 #include <stdint.h>
-#include <unistd.h>
 #include <errno.h>
 #include <sys/mman.h>
 
@@ -12,10 +9,12 @@
 
 void *Thread(void *ptr) {
   *(int*)ptr = 42;
+  barrier_wait(&barrier);
   return 0;
 }
 
 int main() {
+  barrier_init(&barrier, 2);
   void *ptr = mmap(0, 128 << 10, PROT_READ|PROT_WRITE,
       MAP_32BIT|MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
   fprintf(stderr, "ptr=%p\n", ptr);
@@ -29,7 +28,7 @@ int main() {
   }
   pthread_t t;
   pthread_create(&t, 0, Thread, ptr);
-  sleep(1);
+  barrier_wait(&barrier);
   *(int*)ptr = 42;
   pthread_join(t, 0);
   munmap(ptr, 128 << 10);
diff --git a/test/tsan/memcpy_race.cc b/test/tsan/memcpy_race.cc
index 8ec8e0a3e..d49577306 100644
--- a/test/tsan/memcpy_race.cc
+++ b/test/tsan/memcpy_race.cc
@@ -1,9 +1,6 @@
 // RUN: %clangxx_tsan -O1 %s -o %t && %deflake %run %t | FileCheck %s
-#include <pthread.h>
-#include <stddef.h>
-#include <stdio.h>
+#include "test.h"
 #include <string.h>
-#include <unistd.h>
 
 char *data = new char[10];
 char *data1 = new char[10];
@@ -12,17 +9,19 @@ char *data2 = new char[10];
 void *Thread1(void *x) {
   static volatile int size = 1;
   memcpy(data+5, data1, size);
+  barrier_wait(&barrier);
   return NULL;
 }
 
 void *Thread2(void *x) {
   static volatile int size = 4;
-  sleep(1);
+  barrier_wait(&barrier);
   memcpy(data+3, data2, size);
   return NULL;
 }
 
 int main() {
+  barrier_init(&barrier, 2);
   fprintf(stderr, "addr=%p\n", &data[5]);
   pthread_t t[2];
   pthread_create(&t[0], NULL, Thread1, NULL);
diff --git a/test/tsan/mop_with_offset.cc b/test/tsan/mop_with_offset.cc
index e44c78b7d..c67e81e09 100644
--- a/test/tsan/mop_with_offset.cc
+++ b/test/tsan/mop_with_offset.cc
@@ -1,23 +1,22 @@
 // RUN: %clangxx_tsan -O1 %s -o %t && %deflake %run %t | FileCheck %s
-#include <pthread.h>
-#include <stddef.h>
-#include <stdio.h>
-#include <unistd.h>
+#include "test.h"
 
 void *Thread1(void *x) {
   int *p = (int*)x;
   p[0] = 1;
+  barrier_wait(&barrier);
   return NULL;
 }
 
 void *Thread2(void *x) {
-  sleep(1);
+  barrier_wait(&barrier);
   char *p = (char*)x;
   p[2] = 1;
   return NULL;
 }
 
 int main() {
+  barrier_init(&barrier, 2);
   int *data = new int(42);
   fprintf(stderr, "ptr1=%p\n", data);
   fprintf(stderr, "ptr2=%p\n", (char*)data + 2);
diff --git a/test/tsan/mop_with_offset2.cc b/test/tsan/mop_with_offset2.cc
index a465d5f09..460267359 100644
--- a/test/tsan/mop_with_offset2.cc
+++ b/test/tsan/mop_with_offset2.cc
@@ -1,11 +1,8 @@
 // RUN: %clangxx_tsan -O1 %s -o %t && %deflake %run %t | FileCheck %s
-#include <pthread.h>
-#include <stddef.h>
-#include <stdio.h>
-#include <unistd.h>
+#include "test.h"
 
 void *Thread1(void *x) {
-  sleep(1);
+  barrier_wait(&barrier);
   int *p = (int*)x;
   p[0] = 1;
   return NULL;
@@ -14,10 +11,12 @@ void *Thread1(void *x) {
 void *Thread2(void *x) {
   char *p = (char*)x;
   p[2] = 1;
+  barrier_wait(&barrier);
   return NULL;
 }
 
 int main() {
+  barrier_init(&barrier, 2);
   int *data = new int(42);
   fprintf(stderr, "ptr1=%p\n", data);
   fprintf(stderr, "ptr2=%p\n", (char*)data + 2);
diff --git a/test/tsan/mutexset1.cc b/test/tsan/mutexset1.cc
index 72964edfb..407cfe5bd 100644
--- a/test/tsan/mutexset1.cc
+++ b/test/tsan/mutexset1.cc
@@ -1,13 +1,11 @@
 // RUN: %clangxx_tsan -O1 %s -o %t && %deflake %run %t | FileCheck %s
-#include <pthread.h>
-#include <stdio.h>
-#include <unistd.h>
+#include "test.h"
 
 int Global;
 pthread_mutex_t mtx;
 
 void *Thread1(void *x) {
-  sleep(1);
+  barrier_wait(&barrier);
   pthread_mutex_lock(&mtx);
   Global++;
   pthread_mutex_unlock(&mtx);
@@ -16,10 +14,12 @@ void *Thread1(void *x) {
 
 void *Thread2(void *x) {
   Global--;
+  barrier_wait(&barrier);
   return NULL;
 }
 
 int main() {
+  barrier_init(&barrier, 2);
   // CHECK: WARNING: ThreadSanitizer: data race
   // CHECK:   Write of size 4 at {{.*}} by thread T1
   // CHECK:                         (mutexes: write [[M1:M[0-9]+]]):
diff --git a/test/tsan/mutexset2.cc b/test/tsan/mutexset2.cc
index 01a5f5df6..2a3e5bb95 100644
--- a/test/tsan/mutexset2.cc
+++ b/test/tsan/mutexset2.cc
@@ -1,7 +1,5 @@
 // RUN: %clangxx_tsan -O1 %s -o %t && %deflake %run %t | FileCheck %s
-#include <pthread.h>
-#include <stdio.h>
-#include <unistd.h>
+#include "test.h"
 
 int Global;
 pthread_mutex_t mtx;
@@ -10,16 +8,18 @@ void *Thread1(void *x) {
   pthread_mutex_lock(&mtx);
   Global++;
   pthread_mutex_unlock(&mtx);
+  barrier_wait(&barrier);
   return NULL;
 }
 
 void *Thread2(void *x) {
-  sleep(1);
+  barrier_wait(&barrier);
   Global--;
   return NULL;
 }
 
 int main() {
+  barrier_init(&barrier, 2);
   // CHECK: WARNING: ThreadSanitizer: data race
   // CHECK:   Write of size 4 at {{.*}} by thread T2:
   // CHECK:   Previous write of size 4 at {{.*}} by thread T1
diff --git a/test/tsan/mutexset3.cc b/test/tsan/mutexset3.cc
index e14bb1111..ce64cf86e 100644
--- a/test/tsan/mutexset3.cc
+++ b/test/tsan/mutexset3.cc
@@ -1,14 +1,12 @@
 // RUN: %clangxx_tsan -O1 %s -o %t && %deflake %run %t | FileCheck %s
-#include <pthread.h>
-#include <stdio.h>
-#include <unistd.h>
+#include "test.h"
 
 int Global;
 pthread_mutex_t mtx1;
 pthread_mutex_t mtx2;
 
 void *Thread1(void *x) {
-  sleep(1);
+  barrier_wait(&barrier);
   pthread_mutex_lock(&mtx1);
   pthread_mutex_lock(&mtx2);
   Global++;
@@ -19,10 +17,12 @@ void *Thread1(void *x) {
 
 void *Thread2(void *x) {
   Global--;
+  barrier_wait(&barrier);
   return NULL;
 }
 
 int main() {
+  barrier_init(&barrier, 2);
   // CHECK: WARNING: ThreadSanitizer: data race
   // CHECK: Write of size 4 at {{.*}} by thread T1
   // CHECK:               (mutexes: write [[M1:M[0-9]+]], write [[M2:M[0-9]+]]):
diff --git a/test/tsan/mutexset4.cc b/test/tsan/mutexset4.cc
index db860e005..b961efd21 100644
--- a/test/tsan/mutexset4.cc
+++ b/test/tsan/mutexset4.cc
@@ -1,7 +1,5 @@
 // RUN: %clangxx_tsan -O1 %s -o %t && %deflake %run %t | FileCheck %s
-#include <pthread.h>
-#include <stdio.h>
-#include <unistd.h>
+#include "test.h"
 
 int Global;
 pthread_mutex_t mtx1;
@@ -13,16 +11,18 @@ void *Thread1(void *x) {
   Global++;
   pthread_mutex_unlock(&mtx2);
   pthread_mutex_unlock(&mtx1);
+  barrier_wait(&barrier);
   return NULL;
 }
 
 void *Thread2(void *x) {
-  sleep(1);
+  barrier_wait(&barrier);
   Global--;
   return NULL;
 }
 
 int main() {
+  barrier_init(&barrier, 2);
   // CHECK: WARNING: ThreadSanitizer: data race
   // CHECK:   Write of size 4 at {{.*}} by thread T2:
   // CHECK:   Previous write of size 4 at {{.*}} by thread T1
diff --git a/test/tsan/mutexset5.cc b/test/tsan/mutexset5.cc
index e1cc2fcac..8ef9af0ce 100644
--- a/test/tsan/mutexset5.cc
+++ b/test/tsan/mutexset5.cc
@@ -1,14 +1,12 @@
 // RUN: %clangxx_tsan -O1 %s -o %t && %deflake %run %t | FileCheck %s
-#include <pthread.h>
-#include <stdio.h>
-#include <unistd.h>
+#include "test.h"
 
 int Global;
 pthread_mutex_t mtx1;
 pthread_mutex_t mtx2;
 
 void *Thread1(void *x) {
-  sleep(1);
+  barrier_wait(&barrier);
   pthread_mutex_lock(&mtx1);
   Global++;
   pthread_mutex_unlock(&mtx1);
@@ -19,10 +17,12 @@ void *Thread2(void *x) {
   pthread_mutex_lock(&mtx2);
   Global--;
   pthread_mutex_unlock(&mtx2);
+  barrier_wait(&barrier);
   return NULL;
 }
 
 int main() {
+  barrier_init(&barrier, 2);
   // CHECK: WARNING: ThreadSanitizer: data race
   // CHECK:   Write of size 4 at {{.*}} by thread T1
   // CHECK:                              (mutexes: write [[M1:M[0-9]+]]):
diff --git a/test/tsan/mutexset6.cc b/test/tsan/mutexset6.cc
index 07dcc0a73..f4251db69 100644
--- a/test/tsan/mutexset6.cc
+++ b/test/tsan/mutexset6.cc
@@ -1,7 +1,5 @@
 // RUN: %clangxx_tsan -O1 %s -o %t && %deflake %run %t | FileCheck %s
-#include <pthread.h>
-#include <stdio.h>
-#include <unistd.h>
+#include "test.h"
 
 int Global;
 pthread_mutex_t mtx1;
@@ -9,7 +7,7 @@ pthread_spinlock_t mtx2;
 pthread_rwlock_t mtx3;
 
 void *Thread1(void *x) {
-  sleep(1);
+  barrier_wait(&barrier);
   pthread_mutex_lock(&mtx1);
   Global++;
   pthread_mutex_unlock(&mtx1);
@@ -24,10 +22,12 @@ void *Thread2(void *x) {
   Global--;
   pthread_spin_unlock(&mtx2);
   pthread_rwlock_unlock(&mtx3);
+  barrier_wait(&barrier);
   return NULL;
 }
 
 int main() {
+  barrier_init(&barrier, 2);
   // CHECK: WARNING: ThreadSanitizer: data race
   // CHECK:   Write of size 4 at {{.*}} by thread T1
   // CHECK:                          (mutexes: write [[M1:M[0-9]+]]):
diff --git a/test/tsan/mutexset7.cc b/test/tsan/mutexset7.cc
index 12174844c..d3a221d1b 100644
--- a/test/tsan/mutexset7.cc
+++ b/test/tsan/mutexset7.cc
@@ -1,13 +1,11 @@
 // RUN: %clangxx_tsan -O1 %s -o %t && %deflake %run %t | FileCheck %s
-#include <pthread.h>
-#include <stdio.h>
-#include <unistd.h>
+#include "test.h"
 
 int Global;
 __thread int huge[1024*1024];
 
 void *Thread1(void *x) {
-  sleep(1);
+  barrier_wait(&barrier);
   Global++;
   return NULL;
 }
@@ -20,10 +18,12 @@ void *Thread2(void *x) {
   pthread_mutex_unlock(mtx);
   pthread_mutex_destroy(mtx);
   delete mtx;
+  barrier_wait(&barrier);
   return NULL;
 }
 
 int main() {
+  barrier_init(&barrier, 2);
   pthread_t t[2];
   pthread_create(&t[0], NULL, Thread1, NULL);
   pthread_create(&t[1], NULL, Thread2, NULL);
diff --git a/test/tsan/mutexset8.cc b/test/tsan/mutexset8.cc
index 3e1ab8c5a..40d5d043d 100644
--- a/test/tsan/mutexset8.cc
+++ b/test/tsan/mutexset8.cc
@@ -1,13 +1,11 @@
 // RUN: %clangxx_tsan -O1 %s -o %t && %deflake %run %t | FileCheck %s
-#include <pthread.h>
-#include <stdio.h>
-#include <unistd.h>
+#include "test.h"
 
 int Global;
 pthread_mutex_t *mtx;
 
 void *Thread1(void *x) {
-  sleep(1);
+  barrier_wait(&barrier);
   pthread_mutex_lock(mtx);
   Global++;
   pthread_mutex_unlock(mtx);
@@ -16,10 +14,12 @@ void *Thread1(void *x) {
 
 void *Thread2(void *x) {
   Global--;
+  barrier_wait(&barrier);
   return NULL;
 }
 
 int main() {
+  barrier_init(&barrier, 2);
   // CHECK: WARNING: ThreadSanitizer: data race
   // CHECK:   Write of size 4 at {{.*}} by thread T1
   // CHECK:                         (mutexes: write [[M1:M[0-9]+]]):
diff --git a/test/tsan/process_sleep.h b/test/tsan/process_sleep.h
deleted file mode 100644
index 5938a42bf..000000000
--- a/test/tsan/process_sleep.h
+++ /dev/null
@@ -1,7 +0,0 @@
-#include <time.h>
-
-static void process_sleep(int sec) {
-  clock_t beg = clock();
-  while((clock() - beg) / CLOCKS_PER_SEC < sec)
-    usleep(100);
-}
diff --git a/test/tsan/pthread_atfork_deadlock.c b/test/tsan/pthread_atfork_deadlock.c
index 0f33b9022..4aeec82b6 100644
--- a/test/tsan/pthread_atfork_deadlock.c
+++ b/test/tsan/pthread_atfork_deadlock.c
@@ -4,14 +4,12 @@
 // When the data race was reported, pthread_atfork() handler used to be
 // executed which caused another race report in the same thread, which resulted
 // in a deadlock.
-#include <pthread.h>
-#include <stdio.h>
-#include <unistd.h>
+#include "test.h"
 
 int glob = 0;
 
 void *worker(void *unused) {
-  sleep(1);
+  barrier_wait(&barrier);
   glob++;
   return NULL;
 }
@@ -22,10 +20,12 @@ void atfork() {
 }
 
 int main() {
+  barrier_init(&barrier, 2);
   pthread_atfork(atfork, NULL, NULL);
   pthread_t t;
   pthread_create(&t, NULL, worker, NULL);
   glob++;
+  barrier_wait(&barrier);
   pthread_join(t, NULL);
   // CHECK: ThreadSanitizer: data race
   // CHECK-NOT: ATFORK
diff --git a/test/tsan/race_on_barrier.c b/test/tsan/race_on_barrier.c
index 99b18fe4d..cf8a4cb99 100644
--- a/test/tsan/race_on_barrier.c
+++ b/test/tsan/race_on_barrier.c
@@ -1,25 +1,24 @@
 // RUN: %clang_tsan -O1 %s -o %t && %deflake %run %t | FileCheck %s
-#include <pthread.h>
-#include <stdio.h>
-#include <stddef.h>
-#include <unistd.h>
+#include "test.h"
 
 pthread_barrier_t B;
 int Global;
 
 void *Thread1(void *x) {
   pthread_barrier_init(&B, 0, 2);
+  barrier_wait(&barrier);
   pthread_barrier_wait(&B);
   return NULL;
 }
 
 void *Thread2(void *x) {
-  sleep(1);
+  barrier_wait(&barrier);
   pthread_barrier_wait(&B);
   return NULL;
 }
 
 int main() {
+  barrier_init(&barrier, 2);
   pthread_t t;
   pthread_create(&t, NULL, Thread1, NULL);
   Thread2(0);
diff --git a/test/tsan/race_on_mutex.c b/test/tsan/race_on_mutex.c
index b4adeeb4d..7bd461bf3 100644
--- a/test/tsan/race_on_mutex.c
+++ b/test/tsan/race_on_mutex.c
@@ -1,8 +1,5 @@
 // RUN: %clang_tsan -O1 %s -o %t && %deflake %run %t | FileCheck %s
-#include <pthread.h>
-#include <stdio.h>
-#include <stddef.h>
-#include <unistd.h>
+#include "test.h"
 
 pthread_mutex_t Mtx;
 int Global;
@@ -12,11 +9,12 @@ void *Thread1(void *x) {
   pthread_mutex_lock(&Mtx);
   Global = 42;
   pthread_mutex_unlock(&Mtx);
+  barrier_wait(&barrier);
   return NULL;
 }
 
 void *Thread2(void *x) {
-  sleep(1);
+  barrier_wait(&barrier);
   pthread_mutex_lock(&Mtx);
   Global = 43;
   pthread_mutex_unlock(&Mtx);
@@ -24,6 +22,7 @@ void *Thread2(void *x) {
 }
 
 int main() {
+  barrier_init(&barrier, 2);
   pthread_t t[2];
   pthread_create(&t[0], NULL, Thread1, NULL);
   pthread_create(&t[1], NULL, Thread2, NULL);
@@ -36,7 +35,7 @@ int main() {
 // CHECK:      WARNING: ThreadSanitizer: data race
 // CHECK-NEXT:   Atomic read of size 1 at {{.*}} by thread T2:
 // CHECK-NEXT:     #0 pthread_mutex_lock
-// CHECK-NEXT:     #1 Thread2{{.*}} {{.*}}race_on_mutex.c:20{{(:3)?}} ({{.*}})
+// CHECK-NEXT:     #1 Thread2{{.*}} {{.*}}race_on_mutex.c:18{{(:3)?}} ({{.*}})
 // CHECK:        Previous write of size 1 at {{.*}} by thread T1:
 // CHECK-NEXT:     #0 pthread_mutex_init {{.*}} ({{.*}})
-// CHECK-NEXT:     #1 Thread1{{.*}} {{.*}}race_on_mutex.c:11{{(:3)?}} ({{.*}})
+// CHECK-NEXT:     #1 Thread1{{.*}} {{.*}}race_on_mutex.c:8{{(:3)?}} ({{.*}})
diff --git a/test/tsan/race_on_mutex2.c b/test/tsan/race_on_mutex2.c
index 1796d0c64..6ee5438f5 100644
--- a/test/tsan/race_on_mutex2.c
+++ b/test/tsan/race_on_mutex2.c
@@ -1,21 +1,20 @@
 // RUN: %clang_tsan -O1 %s -o %t && %deflake %run %t | FileCheck %s
-#include <pthread.h>
-#include <stdio.h>
-#include <stddef.h>
-#include <unistd.h>
+#include "test.h"
 
 void *Thread(void *x) {
   pthread_mutex_lock((pthread_mutex_t*)x);
   pthread_mutex_unlock((pthread_mutex_t*)x);
+  barrier_wait(&barrier);
   return 0;
 }
 
 int main() {
+  barrier_init(&barrier, 2);
   pthread_mutex_t Mtx;
   pthread_mutex_init(&Mtx, 0);
   pthread_t t;
   pthread_create(&t, 0, Thread, &Mtx);
-  sleep(1);
+  barrier_wait(&barrier);
   pthread_mutex_destroy(&Mtx);
   pthread_join(t, 0);
   return 0;
diff --git a/test/tsan/race_on_puts.cc b/test/tsan/race_on_puts.cc
index 1f2b4db83..f2541823b 100644
--- a/test/tsan/race_on_puts.cc
+++ b/test/tsan/race_on_puts.cc
@@ -1,21 +1,22 @@
 // RUN: %clangxx_tsan -O1 %s -o %t && %deflake %run %t | FileCheck %s
-#include <pthread.h>
-#include <stdio.h>
-#include <unistd.h>
+#include "test.h"
 
 char s[] = "abracadabra";
 
 void *Thread0(void *p) {
   puts(s);
+  barrier_wait(&barrier);
   return 0;
 }
 
 void *Thread1(void *p) {
+  barrier_wait(&barrier);
   s[3] = 'z';
   return 0;
 }
 
 int main() {
+  barrier_init(&barrier, 2);
   pthread_t th[2];
   pthread_create(&th[0], 0, Thread0, 0);
   pthread_create(&th[1], 0, Thread1, 0);
diff --git a/test/tsan/race_on_read.cc b/test/tsan/race_on_read.cc
index 1ec0522b9..d388bbacd 100644
--- a/test/tsan/race_on_read.cc
+++ b/test/tsan/race_on_read.cc
@@ -1,31 +1,35 @@
 // RUN: %clangxx_tsan -O1 %s -o %t && %deflake %run %t | FileCheck %s
-#include <pthread.h>
-#include <stdio.h>
-#include <unistd.h>
+#include "test.h"
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <fcntl.h>
-#include <unistd.h>
 #include <errno.h>
 
 int fd;
 char buf;
 
-void *Thread(void *x) {
-  sleep(1);
+void *Thread1(void *x) {
+  barrier_wait(&barrier);
   read(fd, &buf, 1);
   return NULL;
 }
 
+void *Thread2(void *x) {
+  read(fd, &buf, 1);
+  barrier_wait(&barrier);
+  return NULL;
+}
+
 int main() {
+  barrier_init(&barrier, 2);
   fd = open("/dev/random", O_RDONLY);
   if (fd < 0) {
     fprintf(stderr, "failed to open /dev/random (%d)\n", errno);
     return 1;
   }
   pthread_t t[2];
-  pthread_create(&t[0], NULL, Thread, NULL);
-  pthread_create(&t[1], NULL, Thread, NULL);
+  pthread_create(&t[0], NULL, Thread1, NULL);
+  pthread_create(&t[1], NULL, Thread2, NULL);
   pthread_join(t[0], NULL);
   pthread_join(t[1], NULL);
   close(fd);
diff --git a/test/tsan/race_on_speculative_load.cc b/test/tsan/race_on_speculative_load.cc
index f816db9e8..b50b69677 100644
--- a/test/tsan/race_on_speculative_load.cc
+++ b/test/tsan/race_on_speculative_load.cc
@@ -1,9 +1,8 @@
 // RUN: %clangxx_tsan -O1 %s -o %t && %run %t | FileCheck %s
 // Regtest for https://code.google.com/p/thread-sanitizer/issues/detail?id=40
 // This is a correct program and tsan should not report a race.
-#include <pthread.h>
-#include <unistd.h>
-#include <stdio.h>
+#include "test.h"
+
 int g;
 __attribute__((noinline))
 int foo(int cond) {
@@ -11,17 +10,21 @@ int foo(int cond) {
     return g;
   return 0;
 }
+
 void *Thread1(void *p) {
+  barrier_wait(&barrier);
   long res = foo((long)p);
-  sleep(1);
   return (void*) res;
 }
 
 int main() {
+  barrier_init(&barrier, 2);
   pthread_t t;
   pthread_create(&t, 0, Thread1, 0);
   g = 1;
+  barrier_wait(&barrier);
   pthread_join(t, 0);
   printf("PASS\n");
+  // CHECK-NOT: ThreadSanitizer: data race
   // CHECK: PASS
 }
diff --git a/test/tsan/race_on_write.cc b/test/tsan/race_on_write.cc
index 484bbb7ae..147591a39 100644
--- a/test/tsan/race_on_write.cc
+++ b/test/tsan/race_on_write.cc
@@ -1,7 +1,5 @@
 // RUN: %clangxx_tsan -O1 %s -o %t && %deflake %run %t | FileCheck %s
-#include <pthread.h>
-#include <stdio.h>
-#include <unistd.h>
+#include "test.h"
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <fcntl.h>
@@ -11,7 +9,7 @@ char buf;
 
 void *Thread1(void *x) {
   buf = 1;
-  sleep(1);
+  barrier_wait(&barrier);
   return NULL;
 }
 
@@ -21,11 +19,12 @@ void *Thread2(void *x) {
 }
 
 int main() {
+  barrier_init(&barrier, 2);
   fd = open("/dev/null", O_WRONLY);
   if (fd < 0) return 1;
   pthread_t t[2];
   pthread_create(&t[0], NULL, Thread1, NULL);
-  sleep(1);
+  barrier_wait(&barrier);
   pthread_create(&t[1], NULL, Thread2, NULL);
   pthread_join(t[0], NULL);
   pthread_join(t[1], NULL);
diff --git a/test/tsan/race_with_finished_thread.cc b/test/tsan/race_with_finished_thread.cc
index d28760093..755a7bd98 100644
--- a/test/tsan/race_with_finished_thread.cc
+++ b/test/tsan/race_with_finished_thread.cc
@@ -1,9 +1,5 @@
 // RUN: %clangxx_tsan -O1 %s -o %t && %deflake %run %t | FileCheck %s
-#include <pthread.h>
-#include <stddef.h>
-#include <stdio.h>
-#include <string.h>
-#include <unistd.h>
+#include "test.h"
 
 // Ensure that we can restore a stack of a finished thread.
 
@@ -15,16 +11,19 @@ void __attribute__((noinline)) foobar(int *p) {
 
 void *Thread1(void *x) {
   foobar(&g_data);
+  barrier_wait(&barrier);
   return NULL;
 }
 
 void *Thread2(void *x) {
-  sleep(1);
+  barrier_wait(&barrier);
+  sleep(1); // let the thread finish and exit
   g_data = 43;
   return NULL;
 }
 
 int main() {
+  barrier_init(&barrier, 2);
   pthread_t t[2];
   pthread_create(&t[0], NULL, Thread1, NULL);
   pthread_create(&t[1], NULL, Thread2, NULL);
diff --git a/test/tsan/restore_stack.cc b/test/tsan/restore_stack.cc
index 5dbc279a4..39c11011c 100644
--- a/test/tsan/restore_stack.cc
+++ b/test/tsan/restore_stack.cc
@@ -1,7 +1,5 @@
 // RUN: %clangxx_tsan -O1 %s -o %t && not %run %t 2>&1 | FileCheck %s
-#include <pthread.h>
-#include <stdio.h>
-#include <unistd.h>
+#include "test.h"
 
 int Global;
 volatile int x;
@@ -17,18 +15,21 @@ void *Thread(void *a) {
   __atomic_store_n(&x, 1, __ATOMIC_RELEASE);
   foo();
   data[0]++;
+  if (a != 0)
+    barrier_wait(&barrier);
   return 0;
 }
 
 int main() {
+  barrier_init(&barrier, 2);
   for (int i = 0; i < 50; i++) {
     pthread_t t;
     pthread_create(&t, 0, Thread, 0);
     pthread_join(t, 0);
   }
   pthread_t t;
-  pthread_create(&t, 0, Thread, 0);
-  sleep(5);
+  pthread_create(&t, 0, Thread, (void*)1);
+  barrier_wait(&barrier);
   for (int i = 0; i < kSize; i++)
     data[i]++;
   pthread_join(t, 0);
diff --git a/test/tsan/signal_errno.cc b/test/tsan/signal_errno.cc
index 1fa20f368..8305e8493 100644
--- a/test/tsan/signal_errno.cc
+++ b/test/tsan/signal_errno.cc
@@ -1,10 +1,7 @@
 // RUN: %clang_tsan -O1 %s -o %t && %deflake %run %t | FileCheck %s
-#include <pthread.h>
-#include <stdio.h>
-#include <stdlib.h>
+#include "test.h"
 #include <signal.h>
 #include <sys/types.h>
-#include <unistd.h>
 #include <errno.h>
 
 pthread_t mainth;
@@ -16,12 +13,13 @@ static void MyHandler(int, siginfo_t *s, void *c) {
 }
 
 static void* sendsignal(void *p) {
-  sleep(1);
+  barrier_wait(&barrier);
   pthread_kill(mainth, SIGPROF);
   return 0;
 }
 
 static __attribute__((noinline)) void loop() {
+  barrier_wait(&barrier);
   while (done == 0) {
     volatile char *p = (char*)malloc(1);
     p[0] = 0;
@@ -31,6 +29,7 @@ static __attribute__((noinline)) void loop() {
 }
 
 int main() {
+  barrier_init(&barrier, 2);
   mainth = pthread_self();
   struct sigaction act = {};
   act.sa_sigaction = &MyHandler;
diff --git a/test/tsan/signal_malloc.cc b/test/tsan/signal_malloc.cc
index 06932fba4..1dccb139c 100644
--- a/test/tsan/signal_malloc.cc
+++ b/test/tsan/signal_malloc.cc
@@ -1,9 +1,7 @@
 // RUN: %clang_tsan -O1 %s -o %t && %deflake %run %t | FileCheck %s
-#include <stdio.h>
-#include <stdlib.h>
+#include "test.h"
 #include <signal.h>
 #include <sys/types.h>
-#include <unistd.h>
 
 static void handler(int, siginfo_t*, void*) {
   // CHECK: WARNING: ThreadSanitizer: signal-unsafe call inside of a signal
@@ -20,7 +18,7 @@ int main() {
   act.sa_sigaction = &handler;
   sigaction(SIGPROF, &act, 0);
   kill(getpid(), SIGPROF);
-  sleep(1);
+  sleep(1);  // let the signal handler run
   return 0;
 }
 
diff --git a/test/tsan/signal_recursive.cc b/test/tsan/signal_recursive.cc
index bbb680758..825338de9 100644
--- a/test/tsan/signal_recursive.cc
+++ b/test/tsan/signal_recursive.cc
@@ -3,19 +3,13 @@
 // Test case for recursive signal handlers, adopted from:
 // https://code.google.com/p/thread-sanitizer/issues/detail?id=71
 
-#include <pthread.h>
+#include "test.h"
 #include <semaphore.h>
 #include <signal.h>
-#include <unistd.h>
 #include <errno.h>
-#include <stdlib.h>
-#include <stdio.h>
-
-#include "process_sleep.h"
 
 static const int kSigSuspend = SIGUSR1;
 static const int kSigRestart = SIGUSR2;
-static sigset_t g_suspend_handler_mask;
 
 static sem_t g_thread_suspend_ack_sem;
 
@@ -27,7 +21,7 @@ static void SaveRegistersInStack() {
   // Mono walks thread stacks to detect unreferenced objects.
   // If last object reference is kept in register the object will be collected
   // This is why threads can't be suspended with something like pthread_suspend
-};
+}
 
 static void fail(const char *what) {
   fprintf(stderr, "FAILED: %s (errno=%d)\n", what, errno);
@@ -37,15 +31,19 @@ static void fail(const char *what) {
 static void SuspendHandler(int sig) {
   int old_errno = errno;
   SaveRegistersInStack();
+
+  // Enable kSigRestart handling, tsan disables signals around signal handlers.
+  sigset_t sigset;
+  sigemptyset(&sigset);
+  pthread_sigmask(SIG_SETMASK, &sigset, 0);
+
   // Acknowledge that thread is saved and suspended
   if (sem_post(&g_thread_suspend_ack_sem) != 0)
     fail("sem_post failed");
 
-  do {
-    g_busy_thread_received_restart = false;
-    if (sigsuspend(&g_suspend_handler_mask) != -1 || errno != EINTR)
-      fail("sigsuspend failed");
-  } while (!g_busy_thread_received_restart);
+  // Wait for wakeup signal.
+  while (!g_busy_thread_received_restart)
+    usleep(100);  // wait for kSigRestart signal
 
   // Acknowledge that thread restarted
   if (sem_post(&g_thread_suspend_ack_sem) != 0)
@@ -83,21 +81,15 @@ static void StartWorld(pthread_t thread) {
 static void CollectGarbage(pthread_t thread) {
   StopWorld(thread);
   // Walk stacks
-  process_sleep(1);
   StartWorld(thread);
 }
 
 static void Init() {
-  if (sigfillset(&g_suspend_handler_mask) != 0)
-    fail("sigfillset failed");
-  if (sigdelset(&g_suspend_handler_mask, kSigRestart) != 0)
-    fail("sigdelset failed");
   if (sem_init(&g_thread_suspend_ack_sem, 0, 0) != 0)
     fail("sem_init failed");
 
   struct sigaction act = {};
   act.sa_flags = SA_RESTART;
-  sigfillset(&act.sa_mask);
   act.sa_handler = &SuspendHandler;
   if (sigaction(kSigSuspend, &act, NULL) != 0)
     fail("sigaction failed");
diff --git a/test/tsan/signal_sync.cc b/test/tsan/signal_sync.cc
index 15387b754..6ff19d3bd 100644
--- a/test/tsan/signal_sync.cc
+++ b/test/tsan/signal_sync.cc
@@ -1,11 +1,8 @@
 // RUN: %clang_tsan -O1 %s -o %t && %run %t 2>&1 | FileCheck %s
-#include <pthread.h>
-#include <stdio.h>
-#include <stdlib.h>
+#include "test.h"
 #include <signal.h>
 #include <sys/types.h>
 #include <sys/time.h>
-#include <unistd.h>
 #include <errno.h>
 
 volatile int X;
@@ -18,7 +15,7 @@ static void handler(int sig) {
 
 static void* thr(void *p) {
   for (int i = 0; i != 1000; i++)
-    usleep(1000);
+    usleep(1000);  // process signals
   return 0;
 }
 
diff --git a/test/tsan/signal_write.cc b/test/tsan/signal_write.cc
index 626d87a7a..edb3d2356 100644
--- a/test/tsan/signal_write.cc
+++ b/test/tsan/signal_write.cc
@@ -16,7 +16,7 @@ int main() {
   act.sa_sigaction = &handler;
   sigaction(SIGPROF, &act, 0);
   kill(getpid(), SIGPROF);
-  sleep(1);
+  sleep(1);  // let the signal handler run, can't use barrier in sig handler
   fprintf(stderr, "DONE\n");
   return 0;
 }
diff --git a/test/tsan/simple_race.c b/test/tsan/simple_race.c
index 7b60c5ec2..b4234acd7 100644
--- a/test/tsan/simple_race.c
+++ b/test/tsan/simple_race.c
@@ -1,22 +1,22 @@
 // RUN: %clang_tsan -O1 %s -o %t && %deflake %run %t | FileCheck %s
-#include <pthread.h>
-#include <stdio.h>
-#include <unistd.h>
+#include "test.h"
 
 int Global;
 
 void *Thread1(void *x) {
-  sleep(1);
+  barrier_wait(&barrier);
   Global = 42;
   return NULL;
 }
 
 void *Thread2(void *x) {
   Global = 43;
+  barrier_wait(&barrier);
   return NULL;
 }
 
 int main() {
+  barrier_init(&barrier, 2);
   pthread_t t[2];
   pthread_create(&t[0], NULL, Thread1, NULL);
   pthread_create(&t[1], NULL, Thread2, NULL);
diff --git a/test/tsan/simple_race.cc b/test/tsan/simple_race.cc
index f711bb5d1..612ce2dc0 100644
--- a/test/tsan/simple_race.cc
+++ b/test/tsan/simple_race.cc
@@ -1,22 +1,22 @@
 // RUN: %clangxx_tsan -O1 %s -o %t && %deflake %run %t 2>&1 | FileCheck %s
-#include <pthread.h>
-#include <stdio.h>
-#include <unistd.h>
+#include "test.h"
 
 int Global;
 
 void *Thread1(void *x) {
-  sleep(1);
+  barrier_wait(&barrier);
   Global++;
   return NULL;
 }
 
 void *Thread2(void *x) {
   Global--;
+  barrier_wait(&barrier);
   return NULL;
 }
 
 int main() {
+  barrier_init(&barrier, 2);
   pthread_t t[2];
   pthread_create(&t[0], NULL, Thread1, NULL);
   pthread_create(&t[1], NULL, Thread2, NULL);
diff --git a/test/tsan/simple_stack.c b/test/tsan/simple_stack.c
index 62840c27d..fd8f8ac49 100644
--- a/test/tsan/simple_stack.c
+++ b/test/tsan/simple_stack.c
@@ -1,7 +1,5 @@
 // RUN: %clang_tsan -O1 %s -o %t && %deflake %run %t | FileCheck %s
-#include <pthread.h>
-#include <stdio.h>
-#include <unistd.h>
+#include "test.h"
 
 int Global;
 
@@ -24,13 +22,14 @@ void __attribute__((noinline)) bar2() {
 }
 
 void *Thread1(void *x) {
-  sleep(1);
+  barrier_wait(&barrier);
   bar1();
   return NULL;
 }
 
 void *Thread2(void *x) {
   bar2();
+  barrier_wait(&barrier);
   return NULL;
 }
 
@@ -39,6 +38,7 @@ void StartThread(pthread_t *t, void *(*f)(void*)) {
 }
 
 int main() {
+  barrier_init(&barrier, 2);
   pthread_t t[2];
   StartThread(&t[0], Thread1);
   StartThread(&t[1], Thread2);
@@ -49,18 +49,18 @@ int main() {
 
 // CHECK:      WARNING: ThreadSanitizer: data race
 // CHECK-NEXT:   Write of size 4 at {{.*}} by thread T1:
-// CHECK-NEXT:     #0 foo1{{.*}} {{.*}}simple_stack.c:9{{(:3)?}} ({{.*}})
-// CHECK-NEXT:     #1 bar1{{.*}} {{.*}}simple_stack.c:14{{(:3)?}} ({{.*}})
-// CHECK-NEXT:     #2 Thread1{{.*}} {{.*}}simple_stack.c:28{{(:3)?}} ({{.*}})
+// CHECK-NEXT:     #0 foo1{{.*}} {{.*}}simple_stack.c:7{{(:3)?}} ({{.*}})
+// CHECK-NEXT:     #1 bar1{{.*}} {{.*}}simple_stack.c:12{{(:3)?}} ({{.*}})
+// CHECK-NEXT:     #2 Thread1{{.*}} {{.*}}simple_stack.c:26{{(:3)?}} ({{.*}})
 // CHECK:        Previous read of size 4 at {{.*}} by thread T2:
-// CHECK-NEXT:     #0 foo2{{.*}} {{.*}}simple_stack.c:18{{(:20)?}} ({{.*}})
-// CHECK-NEXT:     #1 bar2{{.*}} {{.*}}simple_stack.c:23{{(:3)?}} ({{.*}})
-// CHECK-NEXT:     #2 Thread2{{.*}} {{.*}}simple_stack.c:33{{(:3)?}} ({{.*}})
+// CHECK-NEXT:     #0 foo2{{.*}} {{.*}}simple_stack.c:16{{(:20)?}} ({{.*}})
+// CHECK-NEXT:     #1 bar2{{.*}} {{.*}}simple_stack.c:21{{(:3)?}} ({{.*}})
+// CHECK-NEXT:     #2 Thread2{{.*}} {{.*}}simple_stack.c:31{{(:3)?}} ({{.*}})
 // CHECK:        Thread T1 (tid={{.*}}, running) created by main thread at:
 // CHECK-NEXT:     #0 pthread_create {{.*}} ({{.*}})
-// CHECK-NEXT:     #1 StartThread{{.*}} {{.*}}simple_stack.c:38{{(:3)?}} ({{.*}})
+// CHECK-NEXT:     #1 StartThread{{.*}} {{.*}}simple_stack.c:37{{(:3)?}} ({{.*}})
 // CHECK-NEXT:     #2 main{{.*}} {{.*}}simple_stack.c:43{{(:3)?}} ({{.*}})
 // CHECK:        Thread T2 ({{.*}}) created by main thread at:
 // CHECK-NEXT:     #0 pthread_create {{.*}} ({{.*}})
-// CHECK-NEXT:     #1 StartThread{{.*}} {{.*}}simple_stack.c:38{{(:3)?}} ({{.*}})
+// CHECK-NEXT:     #1 StartThread{{.*}} {{.*}}simple_stack.c:37{{(:3)?}} ({{.*}})
 // CHECK-NEXT:     #2 main{{.*}} {{.*}}simple_stack.c:44{{(:3)?}} ({{.*}})
diff --git a/test/tsan/simple_stack2.cc b/test/tsan/simple_stack2.cc
index 7044b82a1..719efdf05 100644
--- a/test/tsan/simple_stack2.cc
+++ b/test/tsan/simple_stack2.cc
@@ -1,7 +1,5 @@
 // RUN: %clangxx_tsan -O1 %s -o %T/simple_stack2.cc.exe && %deflake %run %T/simple_stack2.cc.exe | FileCheck %s
-#include <pthread.h>
-#include <stdio.h>
-#include <unistd.h>
+#include "test.h"
 
 int Global;
 
@@ -30,24 +28,26 @@ void __attribute__((noinline)) bar2() {
 }
 
 void *Thread1(void *x) {
-  sleep(1);
+  barrier_wait(&barrier);
   bar1();
   return NULL;
 }
 
 int main() {
+  barrier_init(&barrier, 2);
   pthread_t t;
   pthread_create(&t, NULL, Thread1, NULL);
   bar2();
+  barrier_wait(&barrier);
   pthread_join(t, NULL);
 }
 
 // CHECK:      WARNING: ThreadSanitizer: data race
 // CHECK-NEXT:   Write of size 4 at {{.*}} by thread T1:
-// CHECK-NEXT:     #0 foo1{{.*}} {{.*}}simple_stack2.cc:9{{(:3)?}} (simple_stack2.cc.exe+{{.*}})
-// CHECK-NEXT:     #1 bar1{{.*}} {{.*}}simple_stack2.cc:16{{(:3)?}} (simple_stack2.cc.exe+{{.*}})
-// CHECK-NEXT:     #2 Thread1{{.*}} {{.*}}simple_stack2.cc:34{{(:3)?}} (simple_stack2.cc.exe+{{.*}})
+// CHECK-NEXT:     #0 foo1{{.*}} {{.*}}simple_stack2.cc:7{{(:3)?}} (simple_stack2.cc.exe+{{.*}})
+// CHECK-NEXT:     #1 bar1{{.*}} {{.*}}simple_stack2.cc:14{{(:3)?}} (simple_stack2.cc.exe+{{.*}})
+// CHECK-NEXT:     #2 Thread1{{.*}} {{.*}}simple_stack2.cc:32{{(:3)?}} (simple_stack2.cc.exe+{{.*}})
 // CHECK:        Previous read of size 4 at {{.*}} by main thread:
-// CHECK-NEXT:     #0 foo2{{.*}} {{.*}}simple_stack2.cc:20{{(:22)?}} (simple_stack2.cc.exe+{{.*}})
-// CHECK-NEXT:     #1 bar2{{.*}} {{.*}}simple_stack2.cc:29{{(:3)?}} (simple_stack2.cc.exe+{{.*}})
-// CHECK-NEXT:     #2 main{{.*}} {{.*}}simple_stack2.cc:41{{(:3)?}} (simple_stack2.cc.exe+{{.*}})
+// CHECK-NEXT:     #0 foo2{{.*}} {{.*}}simple_stack2.cc:18{{(:22)?}} (simple_stack2.cc.exe+{{.*}})
+// CHECK-NEXT:     #1 bar2{{.*}} {{.*}}simple_stack2.cc:27{{(:3)?}} (simple_stack2.cc.exe+{{.*}})
+// CHECK-NEXT:     #2 main{{.*}} {{.*}}simple_stack2.cc:40{{(:3)?}} (simple_stack2.cc.exe+{{.*}})
diff --git a/test/tsan/sleep_sync.cc b/test/tsan/sleep_sync.cc
index c7614e16b..b2c6a1220 100644
--- a/test/tsan/sleep_sync.cc
+++ b/test/tsan/sleep_sync.cc
@@ -1,23 +1,25 @@
 // RUN: %clangxx_tsan -O1 %s -o %t && %deflake %run %t | FileCheck %s
-#include <pthread.h>
-#include <unistd.h>
+#include "test.h"
 
 int X = 0;
 
 void MySleep() {
-  sleep(1);
+  sleep(1);  // the sleep that must appear in the report
 }
 
 void *Thread(void *p) {
+  barrier_wait(&barrier);
   MySleep();  // Assume the main thread has done the write.
   X = 42;
   return 0;
 }
 
 int main() {
+  barrier_init(&barrier, 2);
   pthread_t t;
   pthread_create(&t, 0, Thread, 0);
   X = 43;
+  barrier_wait(&barrier);
   pthread_join(t, 0);
   return 0;
 }
diff --git a/test/tsan/sleep_sync2.cc b/test/tsan/sleep_sync2.cc
index 4e616992e..a1a7a3acc 100644
--- a/test/tsan/sleep_sync2.cc
+++ b/test/tsan/sleep_sync2.cc
@@ -1,18 +1,20 @@
 // RUN: %clangxx_tsan -O1 %s -o %t && %deflake %run %t | FileCheck %s
-#include <pthread.h>
-#include <unistd.h>
+#include "test.h"
 
 int X = 0;
 
 void *Thread(void *p) {
   X = 42;
+  barrier_wait(&barrier);
   return 0;
 }
 
 int main() {
+  barrier_init(&barrier, 2);
   pthread_t t;
-  sleep(1);
+  sleep(1);  // must not appear in the report
   pthread_create(&t, 0, Thread, 0);
+  barrier_wait(&barrier);
   X = 43;
   pthread_join(t, 0);
   return 0;
diff --git a/test/tsan/stack_race.cc b/test/tsan/stack_race.cc
index 2e02f46a2..1ada29535 100644
--- a/test/tsan/stack_race.cc
+++ b/test/tsan/stack_race.cc
@@ -1,19 +1,19 @@
 // RUN: %clangxx_tsan -O1 %s -o %t && %deflake %run %t | FileCheck %s
-#include <pthread.h>
-#include <stddef.h>
-#include <unistd.h>
+#include "test.h"
 
 void *Thread(void *a) {
-  sleep(1);
+  barrier_wait(&barrier);
   *(int*)a = 43;
   return 0;
 }
 
 int main() {
+  barrier_init(&barrier, 2);
   int Var = 42;
   pthread_t t;
   pthread_create(&t, 0, Thread, &Var);
   Var = 43;
+  barrier_wait(&barrier);
   pthread_join(t, 0);
 }
 
diff --git a/test/tsan/stack_race2.cc b/test/tsan/stack_race2.cc
index 818db367b..00e31fb96 100644
--- a/test/tsan/stack_race2.cc
+++ b/test/tsan/stack_race2.cc
@@ -1,10 +1,8 @@
 // RUN: %clangxx_tsan -O1 %s -o %t && %deflake %run %t | FileCheck %s
-#include <pthread.h>
-#include <stddef.h>
-#include <unistd.h>
+#include "test.h"
 
 void *Thread2(void *a) {
-  sleep(1);
+  barrier_wait(&barrier);
   *(int*)a = 43;
   return 0;
 }
@@ -14,11 +12,13 @@ void *Thread(void *a) {
   pthread_t t;
   pthread_create(&t, 0, Thread2, &Var);
   Var = 42;
+  barrier_wait(&barrier);
   pthread_join(t, 0);
   return 0;
 }
 
 int main() {
+  barrier_init(&barrier, 2);
   pthread_t t;
   pthread_create(&t, 0, Thread, 0);
   pthread_join(t, 0);
diff --git a/test/tsan/stack_sync_reuse.cc b/test/tsan/stack_sync_reuse.cc
index b1d5619df..5ea9e84b0 100644
--- a/test/tsan/stack_sync_reuse.cc
+++ b/test/tsan/stack_sync_reuse.cc
@@ -1,8 +1,5 @@
 // RUN: %clang_tsan -O1 %s -o %t && %run %t 2>&1 | FileCheck %s
-#include <pthread.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <unistd.h>
+#include "test.h"
 
 // Test case https://code.google.com/p/thread-sanitizer/issues/detail?id=87
 // Tsan sees false HB edge on address pointed to by syncp variable.
@@ -26,7 +23,7 @@ long sink;
 
 void *Thread(void *x) {
   while (__atomic_load_n(&syncp, __ATOMIC_ACQUIRE) == 0)
-    usleep(1000);
+    usleep(1000);  // spin wait
   global = 42;
   __atomic_store_n(syncp, 1, __ATOMIC_RELEASE);
   __atomic_store_n(&syncp, 0, __ATOMIC_RELAXED);
@@ -39,7 +36,7 @@ void __attribute__((noinline)) foobar() {
   __atomic_store_n(&s, 0, __ATOMIC_RELAXED);
   __atomic_store_n(&syncp, &s, __ATOMIC_RELEASE);
   while (__atomic_load_n(&syncp, __ATOMIC_RELAXED) != 0)
-    usleep(1000);
+    usleep(1000);  // spin wait
 }
 
 void __attribute__((noinline)) barfoo() {
diff --git a/test/tsan/suppress_same_address.cc b/test/tsan/suppress_same_address.cc
index df19da1cc..3ec13ee83 100644
--- a/test/tsan/suppress_same_address.cc
+++ b/test/tsan/suppress_same_address.cc
@@ -1,11 +1,10 @@
 // RUN: %clangxx_tsan -O1 %s -o %t && %deflake %run %t | FileCheck %s
-#include <pthread.h>
-#include <unistd.h>
+#include "test.h"
 
 volatile int X;
 
 void *Thread1(void *x) {
-  sleep(1);
+  barrier_wait(&barrier);
   X = 42;
   X = 66;
   X = 78;
@@ -16,10 +15,12 @@ void *Thread2(void *x) {
   X = 11;
   X = 99;
   X = 73;
+  barrier_wait(&barrier);
   return 0;
 }
 
 int main() {
+  barrier_init(&barrier, 2);
   pthread_t t;
   pthread_create(&t, 0, Thread1, 0);
   Thread2(0);
diff --git a/test/tsan/suppressions_race.cc b/test/tsan/suppressions_race.cc
index 4a35c276e..45c30481f 100644
--- a/test/tsan/suppressions_race.cc
+++ b/test/tsan/suppressions_race.cc
@@ -1,22 +1,22 @@
 // RUN: %clang_tsan -O1 %s -o %t && TSAN_OPTIONS="$TSAN_OPTIONS suppressions='%s.supp'" %run %t 2>&1 | FileCheck %s
-#include <pthread.h>
-#include <stdio.h>
-#include <unistd.h>
+#include "test.h"
 
 int Global;
 
 void *Thread1(void *x) {
-  sleep(1);
+  barrier_wait(&barrier);
   Global = 42;
   return NULL;
 }
 
 void *Thread2(void *x) {
   Global = 43;
+  barrier_wait(&barrier);
   return NULL;
 }
 
 int main() {
+  barrier_init(&barrier, 2);
   pthread_t t[2];
   pthread_create(&t[0], NULL, Thread1, NULL);
   pthread_create(&t[1], NULL, Thread2, NULL);
diff --git a/test/tsan/suppressions_race2.cc b/test/tsan/suppressions_race2.cc
index f9827796f..24ecd8ef1 100644
--- a/test/tsan/suppressions_race2.cc
+++ b/test/tsan/suppressions_race2.cc
@@ -1,22 +1,22 @@
 // RUN: %clang_tsan -O1 %s -o %t && TSAN_OPTIONS="$TSAN_OPTIONS suppressions='%s.supp'" %run %t 2>&1 | FileCheck %s
-#include <pthread.h>
-#include <stdio.h>
-#include <unistd.h>
+#include "test.h"
 
 int Global;
 
 void *Thread1(void *x) {
   Global = 42;
+  barrier_wait(&barrier);
   return NULL;
 }
 
 void *Thread2(void *x) {
-  sleep(1);
+  barrier_wait(&barrier);
   Global = 43;
   return NULL;
 }
 
 int main() {
+  barrier_init(&barrier, 2);
   pthread_t t[2];
   pthread_create(&t[0], NULL, Thread1, NULL);
   pthread_create(&t[1], NULL, Thread2, NULL);
diff --git a/test/tsan/test.h b/test/tsan/test.h
new file mode 100644
index 000000000..4496e56cd
--- /dev/null
+++ b/test/tsan/test.h
@@ -0,0 +1,31 @@
+#include <pthread.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <dlfcn.h>
+#include <stddef.h>
+
+// TSan-invisible barrier.
+// Tests use it to establish necessary execution order in a way that does not
+// interfere with tsan (does not establish synchronization between threads).
+__typeof(pthread_barrier_wait) *barrier_wait;
+
+void barrier_init(pthread_barrier_t *barrier, unsigned count) {
+  if (barrier_wait == 0) {
+    void *h = dlopen("libpthread.so.0", RTLD_LAZY);
+    if (h == 0) {
+      fprintf(stderr, "failed to dlopen libpthread.so.0, exiting\n");
+      exit(1);
+    }
+    barrier_wait = (__typeof(barrier_wait))dlsym(h, "pthread_barrier_wait");
+    if (barrier_wait == 0) {
+      fprintf(stderr, "failed to resolve pthread_barrier_wait, exiting\n");
+      exit(1);
+    }
+  }
+  pthread_barrier_init(barrier, 0, count);
+}
+
+// Default instance of the barrier, but a test can declare more manually.
+pthread_barrier_t barrier;
+
diff --git a/test/tsan/thread_detach.c b/test/tsan/thread_detach.c
index 32cf641b1..802d8ded0 100644
--- a/test/tsan/thread_detach.c
+++ b/test/tsan/thread_detach.c
@@ -1,16 +1,16 @@
 // RUN: %clang_tsan -O1 %s -o %t && %run %t 2>&1 | FileCheck %s
-#include <pthread.h>
-#include <stdio.h>
-#include <unistd.h>
+#include "test.h"
 
 void *Thread(void *x) {
+  barrier_wait(&barrier);
   return 0;
 }
 
 int main() {
+  barrier_init(&barrier, 2);
   pthread_t t;
   pthread_create(&t, 0, Thread, 0);
-  sleep(1);
+  barrier_wait(&barrier);
   pthread_detach(t);
   printf("PASS\n");
   return 0;
diff --git a/test/tsan/thread_leak3.c b/test/tsan/thread_leak3.c
index f4db48421..c09fb714d 100644
--- a/test/tsan/thread_leak3.c
+++ b/test/tsan/thread_leak3.c
@@ -1,15 +1,17 @@
 // RUN: %clang_tsan -O1 %s -o %t && %deflake %run %t | FileCheck %s
-#include <pthread.h>
-#include <unistd.h>
+#include "test.h"
 
 void *Thread(void *x) {
+  barrier_wait(&barrier);
   return 0;
 }
 
 int main() {
+  barrier_init(&barrier, 2);
   pthread_t t;
   pthread_create(&t, 0, Thread, 0);
-  sleep(1);
+  barrier_wait(&barrier);
+  sleep(1);  // wait for the thread to finish and exit
   return 0;
 }
 
diff --git a/test/tsan/thread_leak4.c b/test/tsan/thread_leak4.c
index 0d3b83070..1ebca5887 100644
--- a/test/tsan/thread_leak4.c
+++ b/test/tsan/thread_leak4.c
@@ -1,18 +1,18 @@
 // RUN: %clang_tsan -O1 %s -o %t && %run %t 2>&1 | FileCheck %s
-#include <pthread.h>
-#include <unistd.h>
-#include <stdio.h>
+#include "test.h"
 
 void *Thread(void *x) {
-  sleep(10);
+  sleep(100);  // leave the thread "running"
   return 0;
 }
 
 int main() {
   pthread_t t;
   pthread_create(&t, 0, Thread, 0);
-  printf("OK\n");
+  printf("DONE\n");
   return 0;
 }
 
+// CHECK: DONE
 // CHECK-NOT: WARNING: ThreadSanitizer: thread leak
+
diff --git a/test/tsan/thread_leak5.c b/test/tsan/thread_leak5.c
index ca244a9f2..acdbd1d38 100644
--- a/test/tsan/thread_leak5.c
+++ b/test/tsan/thread_leak5.c
@@ -1,18 +1,20 @@
 // RUN: %clang_tsan -O1 %s -o %t && %deflake %run %t | FileCheck %s
-#include <pthread.h>
-#include <unistd.h>
+#include "test.h"
 
 void *Thread(void *x) {
+  barrier_wait(&barrier);
   return 0;
 }
 
 int main() {
   volatile int N = 5;  // prevent loop unrolling
+  barrier_init(&barrier, N + 1);
   for (int i = 0; i < N; i++) {
     pthread_t t;
     pthread_create(&t, 0, Thread, 0);
   }
-  sleep(1);
+  barrier_wait(&barrier);
+  sleep(1);  // wait for the threads to finish and exit
   return 0;
 }
 
diff --git a/test/tsan/thread_name.cc b/test/tsan/thread_name.cc
index a790c668c..80d30b82d 100644
--- a/test/tsan/thread_name.cc
+++ b/test/tsan/thread_name.cc
@@ -1,7 +1,5 @@
 // RUN: %clangxx_tsan -O1 %s -o %t && %deflake %run %t | FileCheck %s
-#include <pthread.h>
-#include <stdio.h>
-#include <unistd.h>
+#include "test.h"
 
 #if defined(__linux__)
 #define USE_PTHREAD_SETNAME_NP __GLIBC_PREREQ(2, 12)
@@ -18,7 +16,7 @@ extern "C" void AnnotateThreadName(const char *f, int l, const char *name);
 int Global;
 
 void *Thread1(void *x) {
-  sleep(1);
+  barrier_wait(&barrier);
   AnnotateThreadName(__FILE__, __LINE__, "Thread1");
   Global++;
   return NULL;
@@ -31,10 +29,12 @@ void *Thread2(void *x) {
   AnnotateThreadName(__FILE__, __LINE__, "Thread2");
 #endif
   Global--;
+  barrier_wait(&barrier);
   return NULL;
 }
 
 int main() {
+  barrier_init(&barrier, 2);
   pthread_t t[2];
   pthread_create(&t[0], NULL, Thread1, NULL);
   pthread_create(&t[1], NULL, Thread2, NULL);
diff --git a/test/tsan/thread_name2.cc b/test/tsan/thread_name2.cc
index 6a3dafe9c..a44f4b9d3 100644
--- a/test/tsan/thread_name2.cc
+++ b/test/tsan/thread_name2.cc
@@ -1,7 +1,5 @@
 // RUN: %clangxx_tsan -O1 %s -o %t && %deflake %run %t | FileCheck %s
-#include <pthread.h>
-#include <stdio.h>
-#include <unistd.h>
+#include "test.h"
 
 #if defined(__FreeBSD__)
 #include <pthread_np.h>
@@ -11,7 +9,7 @@
 int Global;
 
 void *Thread1(void *x) {
-  sleep(1);
+  barrier_wait(&barrier);
   Global++;
   return 0;
 }
@@ -19,14 +17,17 @@ void *Thread1(void *x) {
 void *Thread2(void *x) {
   pthread_setname_np(pthread_self(), "foobar2");
   Global--;
+  barrier_wait(&barrier);
   return 0;
 }
 
 int main() {
+  barrier_init(&barrier, 3);
   pthread_t t[2];
   pthread_create(&t[0], 0, Thread1, 0);
   pthread_create(&t[1], 0, Thread2, 0);
   pthread_setname_np(t[0], "foobar1");
+  barrier_wait(&barrier);
   pthread_join(t[0], NULL);
   pthread_join(t[1], NULL);
 }
diff --git a/test/tsan/tiny_race.c b/test/tsan/tiny_race.c
index c10eab15c..b6937febd 100644
--- a/test/tsan/tiny_race.c
+++ b/test/tsan/tiny_race.c
@@ -1,19 +1,20 @@
 // RUN: %clang_tsan -O1 %s -o %t && %deflake %run %t | FileCheck %s
-#include <pthread.h>
-#include <unistd.h>
+#include "test.h"
 
 int Global;
 
 void *Thread1(void *x) {
-  sleep(1);
+  barrier_wait(&barrier);
   Global = 42;
   return x;
 }
 
 int main() {
+  barrier_init(&barrier, 2);
   pthread_t t;
   pthread_create(&t, 0, Thread1, 0);
   Global = 43;
+  barrier_wait(&barrier);
   pthread_join(t, 0);
   return Global;
 }
diff --git a/test/tsan/tls_race.cc b/test/tsan/tls_race.cc
index 18589347e..5e8172276 100644
--- a/test/tsan/tls_race.cc
+++ b/test/tsan/tls_race.cc
@@ -1,19 +1,19 @@
 // RUN: %clangxx_tsan -O1 %s -o %t && %deflake %run %t | FileCheck %s
-#include <pthread.h>
-#include <stddef.h>
-#include <unistd.h>
+#include "test.h"
 
 void *Thread(void *a) {
-  sleep(1);
+  barrier_wait(&barrier);
   *(int*)a = 43;
   return 0;
 }
 
 int main() {
+  barrier_init(&barrier, 2);
   static __thread int Var = 42;
   pthread_t t;
   pthread_create(&t, 0, Thread, &Var);
   Var = 43;
+  barrier_wait(&barrier);
   pthread_join(t, 0);
 }
 
diff --git a/test/tsan/tls_race2.cc b/test/tsan/tls_race2.cc
index 0ca629ada..d0f7b03e0 100644
--- a/test/tsan/tls_race2.cc
+++ b/test/tsan/tls_race2.cc
@@ -1,10 +1,8 @@
 // RUN: %clangxx_tsan -O1 %s -o %t && %deflake %run %t | FileCheck %s
-#include <pthread.h>
-#include <stddef.h>
-#include <unistd.h>
+#include "test.h"
 
 void *Thread2(void *a) {
-  sleep(1);
+  barrier_wait(&barrier);
   *(int*)a = 43;
   return 0;
 }
@@ -14,11 +12,13 @@ void *Thread(void *a) {
   pthread_t t;
   pthread_create(&t, 0, Thread2, &Var);
   Var = 42;
+  barrier_wait(&barrier);
   pthread_join(t, 0);
   return 0;
 }
 
 int main() {
+  barrier_init(&barrier, 2);
   pthread_t t;
   pthread_create(&t, 0, Thread, 0);
   pthread_join(t, 0);
diff --git a/test/tsan/unaligned_race.cc b/test/tsan/unaligned_race.cc
index 6e9b5a33f..030642a4d 100644
--- a/test/tsan/unaligned_race.cc
+++ b/test/tsan/unaligned_race.cc
@@ -1,9 +1,6 @@
 // RUN: %clangxx_tsan -O1 %s -o %t && %deflake %run %t | FileCheck %s
-#include <pthread.h>
-#include <stdio.h>
-#include <stdlib.h>
+#include "test.h"
 #include <stdint.h>
-#include <unistd.h>
 
 #define NOINLINE __attribute__((noinline))
 
@@ -123,15 +120,17 @@ NOINLINE void Test(bool main) {
 
 void *Thread(void *p) {
   (void)p;
-  sleep(1);
+  barrier_wait(&barrier);
   Test(false);
   return 0;
 }
 
 int main() {
+  barrier_init(&barrier, 2);
   pthread_t th;
   pthread_create(&th, 0, Thread, 0);
   Test(true);
+  barrier_wait(&barrier);
   pthread_join(th, 0);
 }
 
diff --git a/test/tsan/vptr_harmful_race.cc b/test/tsan/vptr_harmful_race.cc
index 68e12e8e7..d15b3969a 100644
--- a/test/tsan/vptr_harmful_race.cc
+++ b/test/tsan/vptr_harmful_race.cc
@@ -1,8 +1,6 @@
 // RUN: %clangxx_tsan -O1 %s -o %t && %deflake %run %t | FileCheck %s
-#include <pthread.h>
+#include "test.h"
 #include <semaphore.h>
-#include <stdio.h>
-#include <unistd.h>
 
 struct A {
   A() {
@@ -31,16 +29,18 @@ static A *obj = new B;
 void *Thread1(void *x) {
   obj->F();
   obj->Done();
+  barrier_wait(&barrier);
   return NULL;
 }
 
 void *Thread2(void *x) {
-  sleep(1);
+  barrier_wait(&barrier);
   delete obj;
   return NULL;
 }
 
 int main() {
+  barrier_init(&barrier, 2);
   pthread_t t[2];
   pthread_create(&t[0], NULL, Thread1, NULL);
   pthread_create(&t[1], NULL, Thread2, NULL);
diff --git a/test/tsan/vptr_harmful_race2.cc b/test/tsan/vptr_harmful_race2.cc
index aa53bbb90..a56b74c09 100644
--- a/test/tsan/vptr_harmful_race2.cc
+++ b/test/tsan/vptr_harmful_race2.cc
@@ -1,8 +1,6 @@
 // RUN: %clangxx_tsan -O1 %s -o %t && %deflake %run %t | FileCheck %s
-#include <pthread.h>
+#include "test.h"
 #include <semaphore.h>
-#include <stdio.h>
-#include <unistd.h>
 
 struct A {
   A() {
@@ -29,18 +27,20 @@ struct B : A {
 static A *obj = new B;
 
 void *Thread1(void *x) {
-  sleep(1);
   obj->F();
+  barrier_wait(&barrier);
   obj->Done();
   return NULL;
 }
 
 void *Thread2(void *x) {
+  barrier_wait(&barrier);
   delete obj;
   return NULL;
 }
 
 int main() {
+  barrier_init(&barrier, 2);
   pthread_t t[2];
   pthread_create(&t[0], NULL, Thread1, NULL);
   pthread_create(&t[1], NULL, Thread2, NULL);
diff --git a/test/tsan/vptr_harmful_race3.cc b/test/tsan/vptr_harmful_race3.cc
index ac6ea94e5..3810a1068 100644
--- a/test/tsan/vptr_harmful_race3.cc
+++ b/test/tsan/vptr_harmful_race3.cc
@@ -1,8 +1,6 @@
 // RUN: %clangxx_tsan -O1 %s -o %t && %deflake %run %t | FileCheck %s
-#include <pthread.h>
+#include "test.h"
 #include <semaphore.h>
-#include <stdio.h>
-#include <unistd.h>
 
 struct A {
   A() {
@@ -30,18 +28,20 @@ static A *obj = new B;
 static void (A::*fn)() = &A::F;
 
 void *Thread1(void *x) {
-  sleep(1);
   (obj->*fn)();
+  barrier_wait(&barrier);
   obj->Done();
   return NULL;
 }
 
 void *Thread2(void *x) {
+  barrier_wait(&barrier);
   delete obj;
   return NULL;
 }
 
 int main() {
+  barrier_init(&barrier, 2);
   pthread_t t[2];
   pthread_create(&t[0], NULL, Thread1, NULL);
   pthread_create(&t[1], NULL, Thread2, NULL);
diff --git a/test/tsan/vptr_harmful_race4.cc b/test/tsan/vptr_harmful_race4.cc
index 969c9d58a..543514de8 100644
--- a/test/tsan/vptr_harmful_race4.cc
+++ b/test/tsan/vptr_harmful_race4.cc
@@ -1,7 +1,5 @@
 // RUN: %clangxx_tsan -O1 %s -o %t && %deflake %run %t | FileCheck %s
-#include <pthread.h>
-#include <stdio.h>
-#include <unistd.h>
+#include "test.h"
 
 struct A {
   virtual void F() {
@@ -17,16 +15,18 @@ struct B : A {
 };
 
 void *Thread(void *x) {
-  sleep(1);
+  barrier_wait(&barrier);
   ((A*)x)->F();
   return 0;
 }
 
 int main() {
+  barrier_init(&barrier, 2);
   A *obj = new B;
   pthread_t t;
   pthread_create(&t, 0, Thread, obj);
   delete obj;
+  barrier_wait(&barrier);
   pthread_join(t, 0);
 }
 
diff --git a/test/tsan/write_in_reader_lock.cc b/test/tsan/write_in_reader_lock.cc
index 55882139b..3f7cb3579 100644
--- a/test/tsan/write_in_reader_lock.cc
+++ b/test/tsan/write_in_reader_lock.cc
@@ -1,6 +1,5 @@
 // RUN: %clangxx_tsan -O1 %s -o %t && %deflake %run %t | FileCheck %s
-#include <pthread.h>
-#include <unistd.h>
+#include "test.h"
 
 pthread_rwlock_t rwlock;
 int GLOB;
@@ -8,14 +7,15 @@ int GLOB;
 void *Thread1(void *p) {
   (void)p;
   pthread_rwlock_rdlock(&rwlock);
+  barrier_wait(&barrier);
   // Write under reader lock.
-  sleep(1);
   GLOB++;
   pthread_rwlock_unlock(&rwlock);
   return 0;
 }
 
 int main(int argc, char *argv[]) {
+  barrier_init(&barrier, 2);
   pthread_rwlock_init(&rwlock, NULL);
   pthread_rwlock_rdlock(&rwlock);
   pthread_t t;
@@ -23,6 +23,7 @@ int main(int argc, char *argv[]) {
   volatile int x = GLOB;
   (void)x;
   pthread_rwlock_unlock(&rwlock);
+  barrier_wait(&barrier);
   pthread_join(t, 0);
   pthread_rwlock_destroy(&rwlock);
   return 0;
@@ -30,6 +31,6 @@ int main(int argc, char *argv[]) {
 
 // CHECK: WARNING: ThreadSanitizer: data race
 // CHECK:   Write of size 4 at {{.*}} by thread T1{{.*}}:
-// CHECK:     #0 Thread1(void*) {{.*}}write_in_reader_lock.cc:13
+// CHECK:     #0 Thread1(void*) {{.*}}write_in_reader_lock.cc:12
 // CHECK:   Previous read of size 4 at {{.*}} by main thread{{.*}}:
 // CHECK:     #0 main {{.*}}write_in_reader_lock.cc:23