[NFCI] [hwasan] Add test demonstrating hwasan lsan false positive (#142874)

Author: fmayer

compiler-rt/test/hwasan/TestCases/Posix/dlerror.cpp

@@ -0,0 +1,30 @@
+// Make sure dlerror is not classified as a leak even if we use dynamic TLS.
+// This is currently not implemented, so this test is XFAIL.
+
+// RUN: %clangxx_hwasan -O0 %s -o %t && HWASAN_OPTIONS=detect_leaks=1 %run %t
+// XFAIL: *
+
+#include <assert.h>
+#include <dlfcn.h>
+#include <pthread.h>
+#include <sanitizer/hwasan_interface.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+constexpr auto kKeys = 500;
+
+int main(int argc, char **argv) {
+  __hwasan_enable_allocator_tagging();
+  // Exhaust static TLS slots to force use of dynamic TLS.
+  pthread_key_t keys[kKeys];
+  for (int i = 0; i < kKeys; ++i) {
+    assert(pthread_key_create(&keys[i], nullptr) == 0);
+  }
+  void *o = dlopen("invalid_file_name.so", 0);
+  const char *err = dlerror();
+  for (int i = 0; i < kKeys; ++i) {
+    assert(pthread_key_delete(keys[i]) == 0);
+  }
+  return 0;
+}