1 files changed, 60 insertions, 0 deletions
diff --git a/test/msan/dtls_test.c b/test/msan/dtls_test.c
new file mode 100644
index 0000000000000..cb88ede2f0a60
--- /dev/null
+++ b/test/msan/dtls_test.c
@@ -0,0 +1,60 @@
+/* RUN: %clang_msan -g -m64 %s -o %t
+   RUN: %clang_msan -g -m64 %s -DBUILD_SO -fPIC -o %t-so.so -shared
+   RUN: %run %t 2>&1
+
+   Regression test for a bug in msan/glibc integration,
+   see https://sourceware.org/bugzilla/show_bug.cgi?id=16291
+   and https://code.google.com/p/memory-sanitizer/issues/detail?id=44
+*/
+
+#ifndef BUILD_SO
+#include <assert.h>
+#include <dlfcn.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <pthread.h>
+
+typedef long *(* get_t)();
+get_t GetTls;
+void *Thread1(void *unused) {
+  long uninitialized;
+  long *x = GetTls();
+  if (*x)
+    fprintf(stderr, "bar\n");
+  *x = uninitialized;
+  fprintf(stderr, "stack: %p dtls: %p\n", &x, x);
+  return 0;
+}
+
+void *Thread2(void *unused) {
+  long *x = GetTls();
+  fprintf(stderr, "stack: %p dtls: %p\n", &x, x);
+  if (*x)
+    fprintf(stderr, "foo\n");   // False negative here.
+  return 0;
+}
+
+int main(int argc, char *argv[]) {
+  char path[4096];
+  snprintf(path, sizeof(path), "%s-so.so", argv[0]);
+  int i;
+
+  void *handle = dlopen(path, RTLD_LAZY);
+  if (!handle) fprintf(stderr, "%s\n", dlerror());
+  assert(handle != 0);
+  GetTls = (get_t)dlsym(handle, "GetTls");
+  assert(dlerror() == 0);
+
+  pthread_t t;
+  pthread_create(&t, 0, Thread1, 0);
+  pthread_join(t, 0);
+  pthread_create(&t, 0, Thread2, 0);
+  pthread_join(t, 0);
+  return 0;
+}
+#else  // BUILD_SO
+__thread long huge_thread_local_array[1 << 17];
+long *GetTls() {
+  return &huge_thread_local_array[0];
+}
+#endif