Merge #16046: util: Add type safe GetTime

fa013664ae23d0682a195b9bded85bc19c99536e util: Add type safe GetTime (MarcoFalke)

Pull request description:

  There are basically two ways to get the time in Bitcoin Core:
  * get the system time (via `GetSystemTimeInSeconds` or `GetTime{Millis,Micros}`)
  * get the mockable time (via `GetTime`)

  Both return the same type (a plain int). This can lead to (test-only) bugs such as 99464bc38e9575ff47f8e33223b252dcea2055e3.

  Fix that by deprecating `GetTime` and adding a `GetTime<>` that returns the mockable time in a non-int type. The new util function is currently unused, but new code should it where possible.

ACKs for commit fa0136:
  promag:
    utACK fa013664.

Tree-SHA512: efab9c463f079fd8fd3030c479637c7b1e8be567a881234bd0f555c8f87e518e3b43ef2466128103db8fc40295aaf24e87ad76d91f338c631246fc703477e95c

1 files changed, 42 insertions, 0 deletions

diff --git a/src/bench/util_time.cpp b/src/bench/util_time.cpp
new file mode 100644
index 0000000000..72d97354aa
--- /dev/null
+++ b/src/bench/util_time.cpp
@@ -0,0 +1,42 @@
+// Copyright (c) 2019 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#include <bench/bench.h>
+
+#include <util/time.h>
+
+static void BenchTimeDeprecated(benchmark::State& state)
+{
+    while (state.KeepRunning()) {
+        (void)GetTime();
+    }
+}
+
+static void BenchTimeMock(benchmark::State& state)
+{
+    SetMockTime(111);
+    while (state.KeepRunning()) {
+        (void)GetTime<std::chrono::seconds>();
+    }
+    SetMockTime(0);
+}
+
+static void BenchTimeMillis(benchmark::State& state)
+{
+    while (state.KeepRunning()) {
+        (void)GetTime<std::chrono::milliseconds>();
+    }
+}
+
+static void BenchTimeMillisSys(benchmark::State& state)
+{
+    while (state.KeepRunning()) {
+        (void)GetTimeMillis();
+    }
+}
+
+BENCHMARK(BenchTimeDeprecated, 100000000);
+BENCHMARK(BenchTimeMillis, 6000000);
+BENCHMARK(BenchTimeMillisSys, 6000000);
+BENCHMARK(BenchTimeMock, 300000000);