Index: compiler-rt/trunk/lib/sanitizer_common/sanitizer_symbolizer_mac.cc
===================================================================
--- compiler-rt/trunk/lib/sanitizer_common/sanitizer_symbolizer_mac.cc
+++ compiler-rt/trunk/lib/sanitizer_common/sanitizer_symbolizer_mac.cc
@@ -37,8 +37,14 @@
   return true;
 }
 
-bool DlAddrSymbolizer::SymbolizeData(uptr addr, DataInfo *info) {
-  return false;
+bool DlAddrSymbolizer::SymbolizeData(uptr addr, DataInfo *datainfo) {
+  Dl_info info;
+  int result = dladdr((const void *)addr, &info);
+  if (!result) return false;
+  const char *demangled = DemangleCXXABI(info.dli_sname);
+  datainfo->name = internal_strdup(demangled);
+  datainfo->start = (uptr)info.dli_saddr;
+  return true;
 }
 
 class AtosSymbolizerProcess : public SymbolizerProcess {
Index: compiler-rt/trunk/test/tsan/Darwin/symbolizer-dladdr.cc
===================================================================
--- compiler-rt/trunk/test/tsan/Darwin/symbolizer-dladdr.cc
+++ compiler-rt/trunk/test/tsan/Darwin/symbolizer-dladdr.cc
@@ -0,0 +1,29 @@
+// RUN: %clangxx_tsan %s -o %t
+// RUN: TSAN_OPTIONS=$TSAN_OPTIONS:verbosity=2:external_symbolizer_path= %deflake %run %t | FileCheck %s
+#include "../test.h"
+
+int GlobalData[10];
+
+void *Thread(void *a) {
+  barrier_wait(&barrier);
+  GlobalData[2] = 42;
+  return 0;
+}
+
+int main() {
+  barrier_init(&barrier, 2);
+  fprintf(stderr, "addr=");
+  print_address(GlobalData);
+  fprintf(stderr, "\n");
+  pthread_t t;
+  pthread_create(&t, 0, Thread, 0);
+  GlobalData[2] = 43;
+  barrier_wait(&barrier);
+  pthread_join(t, 0);
+}
+
+// CHECK: External symbolizer is explicitly disabled.
+// CHECK: Using dladdr symbolizer.
+// CHECK: addr=[[ADDR:0x[0-9,a-f]+]]
+// CHECK: WARNING: ThreadSanitizer: data race
+// CHECK: Location is global 'GlobalData' at [[ADDR]] ({{.*}}+0x{{[0-9,a-f]+}})