1 files changed, 29 insertions, 0 deletions

diff --git a/contrib/llvm-project/llvm/lib/Support/ExponentialBackoff.cpp b/contrib/llvm-project/llvm/lib/Support/ExponentialBackoff.cpp
new file mode 100644
index 000000000000..7e68cf67ad38
--- /dev/null
+++ b/contrib/llvm-project/llvm/lib/Support/ExponentialBackoff.cpp
@@ -0,0 +1,29 @@
+//===- llvm/Support/ExponentialBackoff.h ------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Support/ExponentialBackoff.h"
+#include <thread>
+
+using namespace llvm;
+
+bool ExponentialBackoff::waitForNextAttempt() {
+  auto Now = std::chrono::steady_clock::now();
+  if (Now >= EndTime)
+    return false;
+
+  duration CurMaxWait = std::min(MinWait * CurrentMultiplier, MaxWait);
+  std::uniform_int_distribution<uint64_t> Dist(MinWait.count(),
+                                               CurMaxWait.count());
+  // Use random_device directly instead of a PRNG as uniform_int_distribution
+  // often only takes a few samples anyway.
+  duration WaitDuration = std::min(duration(Dist(RandDev)), EndTime - Now);
+  if (CurMaxWait < MaxWait)
+    CurrentMultiplier *= 2;
+  std::this_thread::sleep_for(WaitDuration);
+  return true;
+}