Index: lib/ubsan/CMakeLists.txt
===================================================================
--- lib/ubsan/CMakeLists.txt
+++ lib/ubsan/CMakeLists.txt
@@ -9,6 +9,7 @@
   )
 
 set(UBSAN_STANDALONE_SOURCES
+  ubsan_diag_standalone.cc
   ubsan_init_standalone.cc
   )
 
Index: lib/ubsan/ubsan_diag_standalone.cc
===================================================================
--- /dev/null
+++ lib/ubsan/ubsan_diag_standalone.cc
@@ -0,0 +1,37 @@
+//===-- ubsan_diag_standalone.cc ------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// Diagnostic reporting for the standalone UBSan runtime.
+//
+//===----------------------------------------------------------------------===//
+
+#include "ubsan_platform.h"
+#if CAN_SANITIZE_UB
+#include "ubsan_diag.h"
+
+using namespace __ubsan;
+
+extern "C" {
+SANITIZER_INTERFACE_ATTRIBUTE
+void __sanitizer_print_stack_trace() {
+  uptr top = 0;
+  uptr bottom = 0;
+  bool request_fast_unwind = common_flags()->fast_unwind_on_fatal;
+  if (request_fast_unwind)
+    __sanitizer::GetThreadStackTopAndBottom(false, &top, &bottom);
+
+  GET_REPORT_OPTIONS(false);
+  BufferedStackTrace stack;
+  stack.Unwind(kStackTraceMax, Opts.pc, Opts.bp, nullptr, 0, 0,
+               request_fast_unwind);
+  stack.Print();
+}
+} // extern "C"
+
+#endif  // CAN_SANITIZE_UB
Index: test/ubsan/TestCases/Common/print-stack-trace.cc
===================================================================
--- /dev/null
+++ test/ubsan/TestCases/Common/print-stack-trace.cc
@@ -0,0 +1,16 @@
+// RUN: %clangxx -fsanitize=undefined -O0 %s -o %t && UBSAN_OPTIONS=stack_trace_format=DEFAULT:fast_unwind_on_fatal=1 %run %t 2>&1 | FileCheck %s
+// RUN: %clangxx -fsanitize=undefined -O0 %s -o %t && UBSAN_OPTIONS=stack_trace_format=DEFAULT:fast_unwind_on_fatal=0 %run %t 2>&1 | FileCheck %s --check-prefix=CHECK-SLOW-UNWIND
+
+#include <sanitizer/common_interface_defs.h>
+
+static inline void FooBarBaz() {
+  __sanitizer_print_stack_trace();
+}
+
+int main() {
+  FooBarBaz();
+  return 0;
+}
+
+// CHECK: {{.*}} in FooBarBaz{{.*}}print-stack-trace.cc{{.*}}
+// CHECK-SLOW-UNWIND: {{.*}} in main{{.*}}print-stack-trace.cc{{.*}}