Index: lib/tsan/rtl/tsan_debugging.cc
===================================================================
--- lib/tsan/rtl/tsan_debugging.cc
+++ lib/tsan/rtl/tsan_debugging.cc
@@ -128,6 +128,16 @@
 }
 
 SANITIZER_INTERFACE_ATTRIBUTE
+int __tsan_get_report_loc_object_type(void *report, uptr idx,
+                                      const char **object_type) {
+  const ReportDesc *rep = (ReportDesc *)report;
+  CHECK_LT(idx, rep->locs.Size());
+  ReportLocation *loc = rep->locs[idx];
+  *object_type = GetObjectTypeFromTag(loc->external_tag);
+  return 1;
+}
+
+SANITIZER_INTERFACE_ATTRIBUTE
 int __tsan_get_report_mutex(void *report, uptr idx, uptr *mutex_id, void **addr,
                             int *destroyed, void **trace, uptr trace_size) {
   const ReportDesc *rep = (ReportDesc *)report;
Index: lib/tsan/rtl/tsan_interface.h
===================================================================
--- lib/tsan/rtl/tsan_interface.h
+++ lib/tsan/rtl/tsan_interface.h
@@ -132,6 +132,10 @@
                           int *fd, int *suppressable, void **trace,
                           uptr trace_size);
 
+SANITIZER_INTERFACE_ATTRIBUTE
+int __tsan_get_report_loc_object_type(void *report, uptr idx,
+                                      const char **object_type);
+
 // Returns information about mutexes included in the report.
 SANITIZER_INTERFACE_ATTRIBUTE
 int __tsan_get_report_mutex(void *report, uptr idx, uptr *mutex_id, void **addr,
Index: test/tsan/debug_external.cc
===================================================================
--- test/tsan/debug_external.cc
+++ test/tsan/debug_external.cc
@@ -0,0 +1,61 @@
+// RUN: %clangxx_tsan -O1 %s -o %t
+// RUN: %deflake %run %t 2>&1 | FileCheck %s
+
+#include <pthread.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+extern "C" {
+void __tsan_on_report(void *report);
+int __tsan_get_report_loc(void *report, unsigned long idx, const char **type,
+                          void **addr, void **start,
+                          unsigned long *size, int *tid, int *fd,
+                          int *suppressable, void **trace,
+                          unsigned long trace_size);
+int __tsan_get_report_loc_object_type(void *report, unsigned long idx,
+                                      const char **object_type);
+void *__tsan_external_register_tag(const char *object_type);
+void __tsan_external_assign_tag(void *addr, void *tag);
+}
+
+void *Thread(void *arg) {
+  *((long *)arg) = 42;
+  return NULL;
+}
+
+int main() {
+  void *tag = __tsan_external_register_tag("MyObject");
+  long *obj = (long *)malloc(sizeof(long));
+  fprintf(stderr, "obj = %p\n", obj);
+  // CHECK: obj = [[ADDR:0x[0-9a-f]+]]
+  __tsan_external_assign_tag(obj, tag);
+
+  pthread_t t;
+  pthread_create(&t, 0, Thread, obj);
+  *obj = 41;
+  pthread_join(t, 0);
+  fprintf(stderr, "Done.\n");
+  return 0;
+}
+
+void __tsan_on_report(void *report) {
+  const char *type;
+  void *addr;
+  void *start;
+  unsigned long size;
+  int tid, fd, suppressable;
+  void *trace[16] = {0};
+  __tsan_get_report_loc(report, 0, &type, &addr, &start, &size, &tid, &fd,
+                        &suppressable, trace, 16);
+  fprintf(stderr, "type = %s, start = %p, size = %ld\n", type, start, size);
+  // CHECK: type = heap, start = [[ADDR]], size = 8
+
+  const char *object_type;
+  __tsan_get_report_loc_object_type(report, 0, &object_type);
+  fprintf(stderr, "object_type = %s\n", object_type);
+  // CHECK: object_type = MyObject
+}
+
+// CHECK: Done.
+// CHECK: ThreadSanitizer: reported 1 warnings