[sanitizer] Test for __sanitizer_get_dtls_size (llvm#108349)

Test for llvm#108348 which is almost NFC. However, the test
may fail on some platforms, and a few iterations could be
needed to filter out unsupported platforms.

Author: vitalybuka

compiler-rt/test/sanitizer_common/TestCases/Linux/tls_get_addr.c

@@ -0,0 +1,52 @@
+// RUN: %clang -g %s -o %t
+// RUN: %clang -g %s -DBUILD_SO -fPIC -o %t-so.so -shared
+// RUN: %run %t 2>&1 | FileCheck %s
+
+// REQUIRES: glibc
+
+// `__tls_get_addr` is somehow not invoked.
+// XFAIL: i386-linux
+
+// These don't intercept __tls_get_addr.
+// XFAIL: lsan,hwasan,ubsan
+
+#ifndef BUILD_SO
+#  include <assert.h>
+#  include <dlfcn.h>
+#  include <pthread.h>
+#  include <stdio.h>
+#  include <stdlib.h>
+
+// CHECK-COUNT-2: __sanitizer_get_dtls_size:
+size_t __sanitizer_get_dtls_size(const void *ptr) {
+  fprintf(stderr, "__sanitizer_get_dtls_size: %p\n", ptr);
+  return 0;
+}
+
+typedef long *(*get_t)();
+get_t GetTls;
+void *Thread(void *unused) { return GetTls(); }
+
+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, Thread, 0);
+  pthread_join(t, 0);
+  pthread_create(&t, 0, Thread, 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