diff --git a/lib/Support/Process.cpp b/lib/Support/Process.cpp
index d5168f03a6d..1360842753d 100644
--- a/lib/Support/Process.cpp
+++ b/lib/Support/Process.cpp
@@ -12,6 +12,11 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/Config/config.h"
+#if LLVM_ON_WIN32
+  // This define makes stdlib.h declare the rand_s function.
+#define _CRT_RAND_S
+#include <stdlib.h>
+#endif
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/Process.h"
 
diff --git a/lib/Support/Windows/Process.inc b/lib/Support/Windows/Process.inc
index 750097eecf4..16e4092e9fa 100644
--- a/lib/Support/Windows/Process.inc
+++ b/lib/Support/Windows/Process.inc
@@ -360,3 +360,10 @@ const char *Process::ResetColor() {
   SetConsoleTextAttribute(GetStdHandle(STD_OUTPUT_HANDLE), defaultColors());
   return 0;
 }
+
+unsigned Process::GetRandomNumber() {
+  unsigned int result;
+  const errno_t ec = rand_s(&result);
+  assert(ec == 0 && "rand_s failed");
+  return result;
+}
diff --git a/unittests/Support/ProcessTest.cpp b/unittests/Support/ProcessTest.cpp
index af6a6f921b0..19694e55d06 100644
--- a/unittests/Support/ProcessTest.cpp
+++ b/unittests/Support/ProcessTest.cpp
@@ -39,6 +39,13 @@ TEST(ProcessTest, SelfProcess) {
   EXPECT_GT(TimeValue::MaxTime, process::get_self()->get_wall_time());
 }
 
+TEST(ProcessTest, GetRandomNumberTest) {
+  const unsigned r1 = Process::GetRandomNumber();
+  const unsigned r2 = Process::GetRandomNumber();
+  // It should be extremely unlikely that both r1 and r2 are 0.
+  EXPECT_NE((r1 | r2), 0);
+}
+
 #ifdef _MSC_VER
 #define setenv(name, var, ignore) _putenv_s(name, var)
 #endif