Add Benchmark to test input de-duplication worst case

Fix nits

replace utiltime?

src/Makefile.bench.include

@@ -18,6 +18,7 @@ bench_bench_bitcoin_SOURCES = \
   bench/block_assemble.cpp \
   bench/checkblock.cpp \
   bench/checkqueue.cpp \
+  bench/duplicate_inputs.cpp \
   bench/examples.cpp \
   bench/rollingbloom.cpp \
   bench/crypto_hash.cpp \

src/bench/duplicate_inputs.cpp

@@ -0,0 +1,100 @@
+// Copyright (c) 2011-2018 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 <chainparams.h>
+#include <coins.h>
+#include <consensus/merkle.h>
+#include <consensus/validation.h>
+#include <miner.h>
+#include <policy/policy.h>
+#include <pow.h>
+#include <scheduler.h>
+#include <txdb.h>
+#include <txmempool.h>
+#include <util/time.h>
+#include <validation.h>
+#include <validationinterface.h>
+
+#include <boost/thread.hpp>
+
+#include <list>
+#include <vector>
+
+
+static void DuplicateInputs(benchmark::State& state)
+{
+    const CScript SCRIPT_PUB{CScript(OP_TRUE)};
+
+    // Switch to regtest so we can mine faster
+    // Also segwit is active, so we can include witness transactions
+    SelectParams(CBaseChainParams::REGTEST);
+
+    InitScriptExecutionCache();
+
+    boost::thread_group thread_group;
+    CScheduler scheduler;
+    const CChainParams& chainparams = Params();
+    {
+        ::pblocktree.reset(new CBlockTreeDB(1 << 20, true));
+        ::pcoinsdbview.reset(new CCoinsViewDB(1 << 23, true));
+        ::pcoinsTip.reset(new CCoinsViewCache(pcoinsdbview.get()));
+
+        thread_group.create_thread(std::bind(&CScheduler::serviceQueue, &scheduler));
+        GetMainSignals().RegisterBackgroundSignalScheduler(scheduler);
+        LoadGenesisBlock(chainparams);
+        CValidationState cvstate;
+        ActivateBestChain(cvstate, chainparams);
+        assert(::chainActive.Tip() != nullptr);
+        const bool witness_enabled{IsWitnessEnabled(::chainActive.Tip(), chainparams.GetConsensus())};
+        assert(witness_enabled);
+    }
+
+    CBlock block{};
+    CMutableTransaction coinbaseTx{};
+    CMutableTransaction naughtyTx{};
+
+    CBlockIndex* pindexPrev = ::chainActive.Tip();
+    assert(pindexPrev != nullptr);
+    block.nBits = GetNextWorkRequired(pindexPrev, &block, chainparams.GetConsensus());
+    block.nNonce = 0;
+    auto nHeight = pindexPrev->nHeight + 1;
+
+    // Make a coinbase TX
+    coinbaseTx.vin.resize(1);
+    coinbaseTx.vin[0].prevout.SetNull();
+    coinbaseTx.vout.resize(1);
+    coinbaseTx.vout[0].scriptPubKey = SCRIPT_PUB;
+    coinbaseTx.vout[0].nValue = GetBlockSubsidy(nHeight, chainparams.GetConsensus());
+    coinbaseTx.vin[0].scriptSig = CScript() << nHeight << OP_0;
+
+
+    naughtyTx.vout.resize(1);
+    naughtyTx.vout[0].nValue = 0;
+    naughtyTx.vout[0].scriptPubKey = SCRIPT_PUB;
+
+    uint64_t n_inputs = (((MAX_BLOCK_SERIALIZED_SIZE / WITNESS_SCALE_FACTOR) - (CTransaction(coinbaseTx).GetTotalSize() + CTransaction(naughtyTx).GetTotalSize())) / 41) - 100;
+    for (uint64_t x = 0; x < (n_inputs - 1); ++x) {
+        naughtyTx.vin.emplace_back(GetRandHash(), 0, CScript(), 0);
+    }
+    naughtyTx.vin.emplace_back(naughtyTx.vin.back());
+
+    block.vtx.push_back(MakeTransactionRef(std::move(coinbaseTx)));
+    block.vtx.push_back(MakeTransactionRef(std::move(naughtyTx)));
+
+    block.hashMerkleRoot = BlockMerkleRoot(block);
+
+    while (state.KeepRunning()) {
+        CValidationState cvstate{};
+        assert(!CheckBlock(block, cvstate, chainparams.GetConsensus(), false, false));
+        assert(cvstate.GetRejectReason() == "bad-txns-inputs-duplicate");
+    }
+
+    thread_group.interrupt_all();
+    thread_group.join_all();
+    GetMainSignals().FlushBackgroundCallbacks();
+    GetMainSignals().UnregisterBackgroundSignalScheduler();
+}
+
+BENCHMARK(DuplicateInputs, 10);