diff --git a/src/third_party/llvm-project/libcxx/benchmarks/GenerateInput.hpp b/src/third_party/llvm-project/libcxx/benchmarks/GenerateInput.hpp
new file mode 100644
index 0000000..8c97f58
--- /dev/null
+++ b/src/third_party/llvm-project/libcxx/benchmarks/GenerateInput.hpp
@@ -0,0 +1,144 @@
+#ifndef BENCHMARK_GENERATE_INPUT_HPP
+#define BENCHMARK_GENERATE_INPUT_HPP
+
+#include <algorithm>
+#include <random>
+#include <vector>
+#include <string>
+#include <climits>
+#include <cstddef>
+
+static const char Letters[] = {
+    '0','1','2','3','4',
+    '5','6','7','8','9',
+    'A','B','C','D','E','F',
+    'G','H','I','J','K',
+    'L','M','N','O','P',
+    'Q','R','S','T','U',
+    'V','W','X','Y','Z',
+    'a','b','c','d','e','f',
+    'g','h','i','j','k',
+    'l','m','n','o','p',
+    'q','r','s','t','u',
+    'v','w','x','y','z'
+};
+static const std::size_t LettersSize = sizeof(Letters);
+
+inline std::default_random_engine& getRandomEngine() {
+    static std::default_random_engine RandEngine(std::random_device{}());
+    return RandEngine;
+}
+
+
+inline char getRandomChar() {
+    std::uniform_int_distribution<> LettersDist(0, LettersSize-1);
+    return Letters[LettersDist(getRandomEngine())];
+}
+
+template <class IntT>
+inline IntT getRandomInteger(IntT Min = 0,
+                             IntT Max = std::numeric_limits<IntT>::max()) {
+    std::uniform_int_distribution<IntT> dist(Min, Max);
+    return dist(getRandomEngine());
+}
+
+inline std::string getRandomString(std::size_t Len) {
+    std::string str(Len, 0);
+    std::generate_n(str.begin(), Len, &getRandomChar);
+    return str;
+}
+
+template <class IntT>
+inline std::vector<IntT> getDuplicateIntegerInputs(size_t N) {
+    std::vector<IntT> inputs(N, static_cast<IntT>(-1));
+    return inputs;
+}
+
+template <class IntT>
+inline std::vector<IntT> getSortedIntegerInputs(size_t N) {
+    std::vector<IntT> inputs;
+    for (size_t i=0; i < N; i += 1)
+        inputs.push_back(i);
+    return inputs;
+}
+
+template <class IntT>
+std::vector<IntT> getSortedLargeIntegerInputs(size_t N) {
+    std::vector<IntT> inputs;
+    for (size_t i=0; i < N; ++i) {
+        inputs.push_back(i + N);
+    }
+    return inputs;
+}
+
+template <class IntT>
+std::vector<IntT> getSortedTopBitsIntegerInputs(size_t N) {
+    std::vector<IntT> inputs = getSortedIntegerInputs<IntT>(N);
+    for (auto& E : inputs) E <<= ((sizeof(IntT) / 2) * CHAR_BIT);
+    return inputs;
+}
+
+template <class IntT>
+inline std::vector<IntT> getReverseSortedIntegerInputs(size_t N) {
+    std::vector<IntT> inputs;
+    std::size_t i = N;
+    while (i > 0) {
+        --i;
+        inputs.push_back(i);
+    }
+    return inputs;
+}
+
+template <class IntT>
+std::vector<IntT> getPipeOrganIntegerInputs(size_t N) {
+    std::vector<IntT> v; v.reserve(N);
+    for (size_t i = 0; i < N/2; ++i) v.push_back(i);
+    for (size_t i = N/2; i < N; ++i) v.push_back(N - i);
+    return v;
+}
+
+
+template <class IntT>
+std::vector<IntT> getRandomIntegerInputs(size_t N) {
+    std::vector<IntT> inputs;
+    for (size_t i=0; i < N; ++i) {
+        inputs.push_back(getRandomInteger<IntT>());
+    }
+    return inputs;
+}
+
+inline std::vector<std::string> getDuplicateStringInputs(size_t N) {
+    std::vector<std::string> inputs(N, getRandomString(1024));
+    return inputs;
+}
+
+inline std::vector<std::string> getRandomStringInputs(size_t N) {
+    std::vector<std::string> inputs;
+    for (size_t i=0; i < N; ++i) {
+        inputs.push_back(getRandomString(1024));
+    }
+    return inputs;
+}
+
+inline std::vector<std::string> getSortedStringInputs(size_t N) {
+    std::vector<std::string> inputs = getRandomStringInputs(N);
+    std::sort(inputs.begin(), inputs.end());
+    return inputs;
+}
+
+inline std::vector<std::string> getReverseSortedStringInputs(size_t N) {
+    std::vector<std::string> inputs = getSortedStringInputs(N);
+    std::reverse(inputs.begin(), inputs.end());
+    return inputs;
+}
+
+inline std::vector<const char*> getRandomCStringInputs(size_t N) {
+    static std::vector<std::string> inputs = getRandomStringInputs(N);
+    std::vector<const char*> cinputs;
+    for (auto const& str : inputs)
+        cinputs.push_back(str.c_str());
+    return cinputs;
+}
+
+
+#endif // BENCHMARK_GENERATE_INPUT_HPP