Index: lib/ubsan/ubsan_init.cc
===================================================================
--- lib/ubsan/ubsan_init.cc
+++ lib/ubsan/ubsan_init.cc
@@ -37,6 +37,7 @@
 static void CommonStandaloneInit() {
   SanitizerToolName = "UndefinedBehaviorSanitizer";
   InitializeFlags();
+  __sanitizer_set_report_path(common_flags()->log_path);
   InitializeCoverage(common_flags()->coverage, common_flags()->coverage_dir);
   CommonInit();
   ubsan_mode = UBSAN_MODE_STANDALONE;
Index: test/ubsan/TestCases/Misc/log-path_test.cc
===================================================================
--- /dev/null
+++ test/ubsan/TestCases/Misc/log-path_test.cc
@@ -0,0 +1,44 @@
+// FIXME: https://code.google.com/p/address-sanitizer/issues/detail?id=316
+// XFAIL: android
+
+// RUN: %clangxx -fsanitize=undefined %s -O1 -o %t
+
+// Regular run.
+// RUN: %run %t -4 2> %t.out
+// RUN: FileCheck %s --check-prefix=CHECK-ERROR < %t.out
+
+// Good log_path.
+// RUN: rm -f %t.log.*
+// RUN: env UBSAN_OPTIONS=log_path=%t.log %run %t -4 2> %t.out
+// RUN: FileCheck %s --check-prefix=CHECK-ERROR < %t.log.*
+
+// Invalid log_path.
+// RUN: env UBSAN_OPTIONS=log_path=/dev/null/INVALID not %run %t -4 2> %t.out
+// RUN: FileCheck %s --check-prefix=CHECK-INVALID < %t.out
+
+// Too long log_path.
+// RUN: env UBSAN_OPTIONS=log_path=`for((i=0;i<10000;i++)); do echo -n $i; done` \
+// RUN:   not %run %t -4 2> %t.out
+// RUN: FileCheck %s --check-prefix=CHECK-LONG < %t.out
+
+// Run w/o errors should not produce any log.
+// RUN: rm -f %t.log.*
+// RUN: env UBSAN_OPTIONS=log_path=%t.log  %run %t 4
+// RUN: not cat %t.log.*
+
+// FIXME: log_path is not supported on Windows yet.
+// XFAIL: win32
+
+#include <stdio.h>
+#include <stdlib.h>
+int main(int argc, char *argv[]) {
+  double a = atof(argv[1]);
+  unsigned int ai = (unsigned int) a;
+  printf("%f %u\n", a, ai);
+  return 0;
+}
+
+// CHECK-ERROR: runtime error: value -4 is outside the range of representable values of type 'unsigned int'
+// CHECK-INVALID: ERROR: Can't open file: /dev/null/INVALID
+// CHECK-LONG: ERROR: Path is too long: 01234
+