From: Dmitry Panin <panin@fb.com>
Date: Thu, 6 Nov 2014 20:47:43 +0000 (-0800)
Subject: Fix integer overflow in folly/Benchmark.cpp
X-Git-Tag: v0.22.0~191
X-Git-Url: http://plrg.eecs.uci.edu/git/?a=commitdiff_plain;h=53c9c964ce4ce3b7b2965dc75b840a9a3f1d2d1c;p=folly.git

Fix integer overflow in folly/Benchmark.cpp

Summary:
`bm_max_secs` has type int32
So when this value is more than 2, expression
```
FLAGS_bm_max_secs * 1000000000;
```
overflows

Test Plan:
I did put a
```
LOG(INFO) << timeBudgetInNs;
```
and observed correct values (before fix they were overflowed)

Reviewed By: antonl@fb.com

Subscribers: njormrod, folly-diffs@

FB internal diff: D1663247

Signature: t1:1663247:1415261814:c9154ffde183b2a4f5403e534e47e52e8276c61b
---

diff --git a/folly/Benchmark.cpp b/folly/Benchmark.cpp
index 940fe91c..66bcf7c1 100644
--- a/folly/Benchmark.cpp
+++ b/folly/Benchmark.cpp
@@ -222,7 +222,7 @@ static double runBenchmarkGetNSPerIteration(const BenchmarkFun& fun,
   static const unsigned int epochs = 1000;
   // We establish a total time budget as we don't want a measurement
   // to take too long. This will curtail the number of actual epochs.
-  const uint64_t timeBudgetInNs = FLAGS_bm_max_secs * 1000000000;
+  const uint64_t timeBudgetInNs = FLAGS_bm_max_secs * 1000000000ULL;
   timespec global;
   CHECK_EQ(0, clock_gettime(CLOCK_REALTIME, &global));