clang-tidy: Add performance-inefficient-vector-operation check

https://clang.llvm.org/extra/clang-tidy/checks/performance/inefficient-vector-operation.html

Author: hebasto

src/.clang-tidy

@@ -7,6 +7,7 @@ modernize-use-default-member-init,
 modernize-use-nullptr,
 performance-faster-string-find,
 performance-for-range-copy,
+performance-inefficient-vector-operation,
 performance-move-const-arg,
 performance-no-automatic-move,
 performance-unnecessary-copy-initialization,

src/bench/lockedpool.cpp

@@ -17,9 +17,7 @@ static void BenchLockedPool(benchmark::Bench& bench)
     const size_t synth_size = 1024*1024;
     Arena b(synth_base, synth_size, 16);
 
-    std::vector<void*> addr;
-    for (int x=0; x<ASIZE; ++x)
-        addr.push_back(nullptr);
+    std::vector<void*> addr{ASIZE, nullptr};
     uint32_t s = 0x12345678;
     bench.run([&] {
         int idx = s & (addr.size() - 1);

src/bench/wallet_create_tx.cpp

@@ -146,6 +146,7 @@ static void AvailableCoins(benchmark::Bench& bench, const std::vector<OutputType
 
     // Generate destinations
     std::vector<CScript> dest_wallet;
+    dest_wallet.reserve(output_type.size());
     for (auto type : output_type) {
         dest_wallet.emplace_back(GetScriptForDestination(getNewDestination(wallet, type)));
     }

src/bitcoin-cli.cpp

@@ -1032,6 +1032,7 @@ static void ParseGetInfoResult(UniValue& result)
     }
 
     std::vector<std::string> formatted_proxies;
+    formatted_proxies.reserve(ordered_proxies.size());
     for (const std::string& proxy : ordered_proxies) {
         formatted_proxies.emplace_back(strprintf("%s (%s)", proxy, Join(proxy_networks.find(proxy)->second, ", ")));
     }

src/bitcoin-util.cpp

@@ -127,6 +127,7 @@ static int Grind(const std::vector<std::string>& args, std::string& strPrint)
 
     std::vector<std::thread> threads;
     int n_tasks = std::max(1u, std::thread::hardware_concurrency());
+    threads.reserve(n_tasks);
     for (int i = 0; i < n_tasks; ++i) {
         threads.emplace_back(grind_task, nBits, header, i, n_tasks, std::ref(found), std::ref(proposed_nonce));
     }

src/node/interfaces.cpp

@@ -241,6 +241,7 @@ class NodeImpl : public Node
         if (command == "") return {};
         ExternalSigner::Enumerate(command, signers, Params().NetworkIDString());
         std::vector<std::unique_ptr<interfaces::ExternalSigner>> result;
+        result.reserve(signers.size());
         for (auto& signer : signers) {
             result.emplace_back(std::make_unique<ExternalSignerImpl>(std::move(signer)));
         }

src/rpc/server.cpp

@@ -83,6 +83,7 @@ std::string CRPCTable::help(const std::string& strCommand, const JSONRPCRequest&
     std::string category;
     std::set<intptr_t> setDone;
     std::vector<std::pair<std::string, const CRPCCommand*> > vCommands;
+    vCommands.reserve(mapCommands.size());
 
     for (const auto& entry : mapCommands)
         vCommands.push_back(make_pair(entry.second.front()->category + entry.first, entry.second.front()));
@@ -513,6 +514,7 @@ static bool ExecuteCommand(const CRPCCommand& command, const JSONRPCRequest& req
 std::vector<std::string> CRPCTable::listCommands() const
 {
     std::vector<std::string> commandList;
+    commandList.reserve(mapCommands.size());
     for (const auto& i : mapCommands) commandList.emplace_back(i.first);
     return commandList;
 }

src/rpc/util.cpp

@@ -608,6 +608,7 @@ bool RPCHelpMan::IsValidNumArgs(size_t num_args) const
 std::vector<std::string> RPCHelpMan::GetArgNames() const
 {
     std::vector<std::string> ret;
+    ret.reserve(m_args.size());
     for (const auto& arg : m_args) {
         ret.emplace_back(arg.m_names);
     }

src/script/descriptor.cpp

@@ -830,6 +830,7 @@ class MultiADescriptor final : public DescriptorImpl
     std::vector<CScript> MakeScripts(const std::vector<CPubKey>& keys, Span<const CScript>, FlatSigningProvider&) const override {
         CScript ret;
         std::vector<XOnlyPubKey> xkeys;
+        xkeys.reserve(keys.size());
         for (const auto& key : keys) xkeys.emplace_back(key);
         if (m_sorted) std::sort(xkeys.begin(), xkeys.end());
         ret << ToByteVector(xkeys[0]) << OP_CHECKSIG;

src/test/allocator_tests.cpp

@@ -77,6 +77,7 @@ BOOST_AUTO_TEST_CASE(arena_tests)
     b.walk();
 #endif
     // Sweeping allocate all memory
+    addr.reserve(2048);
     for (int x=0; x<1024; ++x)
         addr.push_back(b.alloc(1024));
     BOOST_CHECK(b.stats().free == 0);