make straus cached mode thread safe, and add tests for it

tests/performance_tests/main.cpp

@@ -221,6 +221,13 @@ int main(int argc, char** argv)
   TEST_PERFORMANCE2(filter, verbose, test_multiexp, multiexp_straus, 1024);
   TEST_PERFORMANCE2(filter, verbose, test_multiexp, multiexp_straus, 4096);
 
+  TEST_PERFORMANCE2(filter, verbose, test_multiexp, multiexp_straus_cached, 2);
+  TEST_PERFORMANCE2(filter, verbose, test_multiexp, multiexp_straus_cached, 8);
+  TEST_PERFORMANCE2(filter, verbose, test_multiexp, multiexp_straus_cached, 16);
+  TEST_PERFORMANCE2(filter, verbose, test_multiexp, multiexp_straus_cached, 256);
+  TEST_PERFORMANCE2(filter, verbose, test_multiexp, multiexp_straus_cached, 1024);
+  TEST_PERFORMANCE2(filter, verbose, test_multiexp, multiexp_straus_cached, 4096);
+
   std::cout << "Tests finished. Elapsed time: " << timer.elapsed_ms() / 1000 << " sec" << std::endl;
 
   return 0;

tests/performance_tests/multiexp.h

@@ -38,6 +38,7 @@ enum test_multiexp_algorithm
 {
   multiexp_bos_coster,
   multiexp_straus,
+  multiexp_straus_cached,
 };
 
 template<test_multiexp_algorithm algorithm, size_t npoints>
@@ -59,6 +60,7 @@ public:
       rct::key kn = rct::scalarmultKey(point, data[n].scalar);
       res = rct::addKeys(res, kn);
     }
+    cache = rct::straus_init_cache(data);
     return true;
   }
 
@@ -69,7 +71,9 @@ public:
       case multiexp_bos_coster:
         return res == bos_coster_heap_conv_robust(data);
       case multiexp_straus:
-        return res == straus(data, false);
+        return res == straus(data);
+      case multiexp_straus_cached:
+        return res == straus(data, cache);
       default:
         return false;
     }
@@ -77,5 +81,6 @@ public:
 
 private:
   std::vector<rct::MultiexpData> data;
+  std::shared_ptr<rct::straus_cached_data> cache;
   rct::key res;
 };

tests/unit_tests/CMakeLists.txt

@@ -58,6 +58,7 @@ set(unit_tests_sources
   mlocker.cpp
   mnemonics.cpp
   mul_div.cpp
+  multiexp.cpp
   multisig.cpp
   parse_amount.cpp
   random.cpp

tests/unit_tests/multiexp.cpp

@@ -0,0 +1,149 @@
+// Copyright (c) 2018, The Monero Project
+// 
+// All rights reserved.
+// 
+// Redistribution and use in source and binary forms, with or without modification, are
+// permitted provided that the following conditions are met:
+// 
+// 1. Redistributions of source code must retain the above copyright notice, this list of
+//    conditions and the following disclaimer.
+// 
+// 2. Redistributions in binary form must reproduce the above copyright notice, this list
+//    of conditions and the following disclaimer in the documentation and/or other
+//    materials provided with the distribution.
+// 
+// 3. Neither the name of the copyright holder nor the names of its contributors may be
+//    used to endorse or promote products derived from this software without specific
+//    prior written permission.
+// 
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
+// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
+// THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+// STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
+// THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include "gtest/gtest.h"
+
+#include "crypto/crypto.h"
+#include "ringct/rctOps.h"
+#include "ringct/multiexp.h"
+
+static const rct::key TESTSCALAR = rct::H;
+static const rct::key TESTPOINT = rct::scalarmultBase(rct::H);
+
+static rct::key basic(const std::vector<rct::MultiexpData> &data)
+{
+  ge_p3 res_p3 = ge_p3_identity;
+  for (const auto &d: data)
+  {
+    ge_cached cached;
+    ge_p3 p3;
+    ge_p1p1 p1;
+    ge_scalarmult_p3(&p3, d.scalar.bytes, &d.point);
+    ge_p3_to_cached(&cached, &p3);
+    ge_add(&p1, &res_p3, &cached);
+    ge_p1p1_to_p3(&res_p3, &p1);
+  }
+  rct::key res;
+  ge_p3_tobytes(res.bytes, &res_p3);
+  return res;
+}
+
+static ge_p3 get_p3(const rct::key &point)
+{
+  ge_p3 p3;
+  EXPECT_TRUE(ge_frombytes_vartime(&p3, point.bytes) == 0);
+  return p3;
+}
+
+TEST(multiexp, bos_coster_empty)
+{
+  std::vector<rct::MultiexpData> data;
+  data.push_back({rct::zero(), get_p3(rct::identity())});
+  ASSERT_TRUE(basic(data) == bos_coster_heap_conv_robust(data));
+}
+
+TEST(multiexp, straus_empty)
+{
+  std::vector<rct::MultiexpData> data;
+  data.push_back({rct::zero(), get_p3(rct::identity())});
+  ASSERT_TRUE(basic(data) == straus(data));
+}
+
+TEST(multiexp, bos_coster_only_zeroes)
+{
+  std::vector<rct::MultiexpData> data;
+  for (int n = 0; n < 16; ++n)
+    data.push_back({rct::zero(), get_p3(TESTPOINT)});
+  ASSERT_TRUE(basic(data) == bos_coster_heap_conv_robust(data));
+}
+
+TEST(multiexp, straus_only_zeroes)
+{
+  std::vector<rct::MultiexpData> data;
+  for (int n = 0; n < 16; ++n)
+    data.push_back({rct::zero(), get_p3(TESTPOINT)});
+  ASSERT_TRUE(basic(data) == straus(data));
+}
+
+TEST(multiexp, bos_coster_only_identities)
+{
+  std::vector<rct::MultiexpData> data;
+  for (int n = 0; n < 16; ++n)
+    data.push_back({TESTSCALAR, get_p3(rct::identity())});
+  ASSERT_TRUE(basic(data) == bos_coster_heap_conv_robust(data));
+}
+
+TEST(multiexp, straus_only_identities)
+{
+  std::vector<rct::MultiexpData> data;
+  for (int n = 0; n < 16; ++n)
+    data.push_back({TESTSCALAR, get_p3(rct::identity())});
+  ASSERT_TRUE(basic(data) == straus(data));
+}
+
+TEST(multiexp, bos_coster_random)
+{
+  std::vector<rct::MultiexpData> data;
+  for (int n = 0; n < 32; ++n)
+  {
+    data.push_back({rct::skGen(), get_p3(rct::scalarmultBase(rct::skGen()))});
+    ASSERT_TRUE(basic(data) == bos_coster_heap_conv_robust(data));
+  }
+}
+
+TEST(multiexp, straus_random)
+{
+  std::vector<rct::MultiexpData> data;
+  for (int n = 0; n < 32; ++n)
+  {
+    data.push_back({rct::skGen(), get_p3(rct::scalarmultBase(rct::skGen()))});
+    ASSERT_TRUE(basic(data) == straus(data));
+  }
+}
+
+TEST(multiexp, straus_cached)
+{
+  static constexpr size_t N = 256;
+  std::vector<rct::MultiexpData> P(N);
+  for (size_t n = 0; n < N; ++n)
+  {
+    P[n].scalar = rct::zero();
+    ASSERT_TRUE(ge_frombytes_vartime(&P[n].point, rct::scalarmultBase(rct::skGen()).bytes) == 0);
+  }
+  std::shared_ptr<rct::straus_cached_data> cache = rct::straus_init_cache(P);
+  for (size_t n = 0; n < N/16; ++n)
+  {
+    std::vector<rct::MultiexpData> data;
+    size_t sz = 1 + crypto::rand<size_t>() % (N-1);
+    for (size_t s = 0; s < sz; ++s)
+    {
+      data.push_back({rct::skGen(), P[s].point});
+    }
+    ASSERT_TRUE(basic(data) == straus(data, cache));
+  }
+}