Index: lib/hwasan/hwasan.cc
===================================================================
--- lib/hwasan/hwasan.cc
+++ lib/hwasan/hwasan.cc
@@ -363,6 +363,14 @@
   TagMemoryAligned(p, sz, tag);
 }
 
+static const u8 kFallbackTag = 0xBB;
+
+u8 __hwasan_generate_tag() {
+  HwasanThread *t = GetCurrentThread();
+  if (!t) return kFallbackTag;
+  return t->GenerateRandomTag();
+}
+
 #if !SANITIZER_SUPPORTS_WEAK_HOOKS
 extern "C" {
 SANITIZER_INTERFACE_ATTRIBUTE SANITIZER_WEAK_ATTRIBUTE
Index: lib/hwasan/hwasan_interface_internal.h
===================================================================
--- lib/hwasan/hwasan_interface_internal.h
+++ lib/hwasan/hwasan_interface_internal.h
@@ -86,6 +86,9 @@
 SANITIZER_INTERFACE_ATTRIBUTE
 void __hwasan_tag_memory(uptr p, u8 tag, uptr sz);
 
+SANITIZER_INTERFACE_ATTRIBUTE
+u8 __hwasan_generate_tag();
+
 // Returns the offset of the first tag mismatch or -1 if the whole range is
 // good.
 SANITIZER_INTERFACE_ATTRIBUTE
Index: test/hwasan/lit.cfg
===================================================================
--- test/hwasan/lit.cfg
+++ test/hwasan/lit.cfg
@@ -9,7 +9,7 @@
 config.test_source_root = os.path.dirname(__file__)
 
 # Setup default compiler flags used with -fsanitize=memory option.
-clang_hwasan_cflags = ["-fsanitize=hwaddress", config.target_cflags] + config.debug_info_flags
+clang_hwasan_cflags = ["-fsanitize=hwaddress", "-mllvm", "-hwasan-generate-tags-with-calls", config.target_cflags] + config.debug_info_flags
 clang_hwasan_cxxflags = config.cxx_mode_flags + clang_hwasan_cflags
 
 def build_invocation(compile_flags):