test/cctest/test-swiss-name-dictionary-shared-tests.h

// Copyright 2021 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef V8_TEST_CCTEST_TEST_SWISS_HASH_TABLE_SHARED_TESTS_H_
#define V8_TEST_CCTEST_TEST_SWISS_HASH_TABLE_SHARED_TESTS_H_

#include <algorithm>
#include <string>

#include "test/cctest/test-swiss-name-dictionary-infra.h"

namespace v8 {
namespace internal {
namespace test_swiss_hash_table {

// The name of the test-*.cc file that executes the tests below with the
// RuntimeTestRunner.
extern const char kRuntimeTestFileName[];

// The name of the test-*.cc file that executes the tests below with the
// CSATestRunner.
extern const char kCSATestFileName[];

// This class  contains test cases for SwissNameDictionary that can be executed
// by different "test runners", which are supplied as a template parameter. The
// TestRunner determines how the operations on dictionaries are actually
// executed. Currently there are two TestRunners: RuntimeTestRunner calls C++
// functions, whereas CSATestRunner executes dictionary operations by executing
// CSA-generated code.
// To execute the tests, just create an instance of the class below with an
// appropriate TestRunner.
// Whenever creating an instance of this class in a file bar.cc, the template
// parameter |kTestFileName| should be set to the name of the file that
// *instantiates the class* (i.e., "bar.cc"). This ensures that the tests
// defined below are then registred within the overall cctest machinery as if
// they were directly written within bar.cc.
template <typename TestRunner, char const* kTestFileName>
struct SharedSwissTableTests {
  static_assert((std::is_same<TestRunner, RuntimeTestRunner>::value) ||
                (std::is_same<TestRunner, CSATestRunner>::value));

  SharedSwissTableTests() {
    CHECK(kTestFileName == kRuntimeTestFileName ||
          kTestFileName == kCSATestFileName);
  }

  using TS = TestSequence<TestRunner>;

  //
  // Helpers
  //

  // We add this value when we want to create fake H1 values to prevent us from
  // accidentally creating an overall hash of 0, which is forbidden. Due to all
  // H1 values are used modulo the capacity of the table, this has no further
  // effects. Note that using just this value itself as an H1 value means that a
  // key will (try to) occupy bucket 0.
  static const int kBigModulus = (1 << 22);
  static_assert(SwissNameDictionary::IsValidCapacity(kBigModulus));

  // Returns elements from TS::distinct_property_details in a determinstic
  // order. Subsequent calls with increasing |index| (and the same |offset|)
  // will return pairwise different values until |index| has risen by more than
  // {TS::distinct_property_details.size()}.
  static PropertyDetails distinct_details(int index, int offset = 0) {
    int size = static_cast<int>(distinct_property_details.size());
    return distinct_property_details[(index + offset) % size];
  }

  // Adds elements at the boundaries of the table, e.g. to buckets 0, 1,
  // Capacity() - 2, and Capacity() - 1. (But only three of those if the table
  // can't hold 4 elements without resizing).
  static void AddAtBoundaries(TS& s) {
    int capacity = s.initial_capacity;
    std::vector<int> interesting_indices = s.boundary_indices(capacity);

    s.CheckCounts(capacity, 0, 0);

    int count = 0;
    for (int index : interesting_indices) {
      std::string key = "k" + std::to_string(index);
      std::string value = "v" + std::to_string(index);
      PropertyDetails details = distinct_details(count++);
      s.Add(Key{key, FakeH1{index + kBigModulus}}, value, details);
    }

    // We didn't want to cause a resize:
    s.CheckCounts(capacity);
  }

  // Adds |count| entries to the table, using their unmodified hashes, of the
  // form key_i -> (value_i, details_i), where key_i and value_i are build from
  // appending the actual index (e.g., 0, ...., counts - 1) to |key_prefix| and
  // |value_prefix|, respectively. The property details are taken from
  // |distinct_property_details|.
  static void AddMultiple(TS& s, int count, std::string key_prefix = "key",
                          std::string value_prefix = "value",
                          int details_offset = 0) {
    for (int i = 0; i < count; ++i) {
      std::string key = key_prefix + std::to_string(i);
      std::string value = value_prefix + std::to_string(i);
      PropertyDetails d = distinct_details(i);
      s.Add(Key{key}, value, d);
    }
  }

  // Checks that |count| entries exist, as they would have been added by a call
  // to AddMultiple with the same arguments.
  static void CheckMultiple(TS& s, int count, std::string key_prefix = "key",
                            std::string value_prefix = "value",
                            int details_offset = 0) {
    DCHECK_LE(count,
              SwissNameDictionary::MaxUsableCapacity(s.initial_capacity));

    std::vector<std::string> expected_keys;
    for (int i = 0; i < count; ++i) {
      std::string key = key_prefix + std::to_string(i);
      expected_keys.push_back(key);
      std::string value = value_prefix + std::to_string(i);
      int details_index =
          (details_offset + i) % distinct_property_details.size();
      PropertyDetails d = distinct_property_details[details_index];
      s.CheckDataAtKey(Key{key}, kIndexUnknown, value, d);
    }
    s.CheckEnumerationOrder(expected_keys);
  }

  //
  // Start of actual tests.
  //

  MEMBER_TEST(Allocation) {
    TS::WithAllInterestingInitialCapacities([](TS& s) {
      // The test runner does the allocation automatically.
      s.CheckCounts(s.initial_capacity, 0, 0);
      s.VerifyHeap();
    });
  }

  // Simple test for adding entries. Also uses non-Symbol keys and non-String
  // values, which is not supported by the higher-level testing infrastructure.
  MEMBER_TEST(SimpleAdd) {
    // TODO(v8:11330): Remove once CSA implementation has a fallback for
    // non-SSSE3/AVX configurations.
    if (!TestRunner::IsEnabled()) return;
    TS::WithInitialCapacity(4, [](TS& s) {
      Handle<String> key1 = s.isolate->factory()->InternalizeUtf8String("foo");
      Handle<String> value1 =
          s.isolate->factory()->InternalizeUtf8String("bar");
      PropertyDetails details1 =
          PropertyDetails(PropertyKind::kData, PropertyAttributes::DONT_DELETE,
                          PropertyCellType::kNoCell);

      s.CheckCounts(4, 0, 0);
      s.CheckKeyAbsent(key1);

      s.Add(key1, value1, details1);
      s.CheckDataAtKey(key1, kIndexUnknown, value1, details1);
      s.CheckCounts(4, 1, 0);

      Handle<Symbol> key2 = s.isolate->factory()->NewSymbol();
      Handle<Smi> value2 = handle(Smi::FromInt(123), s.isolate);
      PropertyDetails details2 =
          PropertyDetails(PropertyKind::kData, PropertyAttributes::DONT_DELETE,
                          PropertyCellType::kNoCell);

      s.CheckKeyAbsent(key2);
      s.Add(key2, value2, details2);
      s.CheckDataAtKey(key2, kIndexUnknown, value2, details2);
      s.CheckCounts(4, 2, 0);
    });
  }

  // Simple test for updating existing entries. Also uses non-Symbol keys and
  // non-String values, which is not supported by the higher-level testing
  // infrastructure.
  MEMBER_TEST(SimpleUpdate) {
    // TODO(v8:11330): Remove once CSA implementation has a fallback for
    // non-SSSE3/AVX configurations.
    if (!TestRunner::IsEnabled()) return;
    TS::WithInitialCapacity(4, [](TS& s) {
      Handle<String> key1 = s.isolate->factory()->InternalizeUtf8String("foo");
      Handle<String> value1 =
          s.isolate->factory()->InternalizeUtf8String("bar");
      PropertyDetails details1 =
          PropertyDetails(PropertyKind::kData, PropertyAttributes::DONT_DELETE,
                          PropertyCellType::kNoCell);

      s.Add(key1, value1, details1);

      Handle<Symbol> key2 = s.isolate->factory()->NewSymbol();
      Handle<Smi> value2 = handle(Smi::FromInt(123), s.isolate);
      PropertyDetails details2 =
          PropertyDetails(PropertyKind::kData, PropertyAttributes::DONT_DELETE,
                          PropertyCellType::kNoCell);

      s.Add(key2, value2, details2);

      // Until here same operations as in Test "Add".

      Handle<Smi> value1_updated = handle(Smi::FromInt(456), s.isolate);
      Handle<String> value2_updated =
          s.isolate->factory()->InternalizeUtf8String("updated");
      PropertyDetails details1_updated = details2;
      PropertyDetails details2_updated = details1;

      s.UpdateByKey(key1, value1_updated, details1_updated);
      s.CheckDataAtKey(key1, kIndexUnknown, value1_updated, details1_updated);
      s.CheckDataAtKey(key2, kIndexUnknown, value2, details2);

      s.UpdateByKey(key2, value2_updated, details2_updated);
      s.CheckDataAtKey(key1, kIndexUnknown, value1_updated, details1_updated);
      s.CheckDataAtKey(key2, kIndexUnknown, value2_updated, details2_updated);
      s.CheckCounts(4, 2, 0);
    });
  }

  // Simple test for deleting existing entries. Also uses non-Symbol keys and
  // non-String values, which is not supported by the higher-level testing
  // infrastructure.
  MEMBER_TEST(SimpleDelete) {
    // TODO(v8:11330): Remove once CSA implementation has a fallback for
    // non-SSSE3/AVX configurations.
    if (!TestRunner::IsEnabled()) return;
    TS::WithInitialCapacity(4, [](TS& s) {
      Handle<String> key1 = s.isolate->factory()->InternalizeUtf8String("foo");
      Handle<String> value1 =
          s.isolate->factory()->InternalizeUtf8String("bar");
      PropertyDetails details1 =
          PropertyDetails(PropertyKind::kData, PropertyAttributes::DONT_DELETE,
                          PropertyCellType::kNoCell);

      s.Add(key1, value1, details1);

      Handle<Symbol> key2 = s.isolate->factory()->NewSymbol();
      Handle<Smi> value2 = handle(Smi::FromInt(123), s.isolate);
      PropertyDetails details2 =
          PropertyDetails(PropertyKind::kData, PropertyAttributes::DONT_DELETE,
                          PropertyCellType::kNoCell);

      s.Add(key2, value2, details2);

      // Until here same operations as in Test "Add".

      s.DeleteByKey(key1);
      s.CheckKeyAbsent(key1);
      s.CheckDataAtKey(key2, kIndexUnknown, value2, details2);
      s.CheckCounts(4, 1, 1);

      s.DeleteByKey(key2);
      s.CheckKeyAbsent(key1);
      s.CheckKeyAbsent(key2);
      s.CheckCounts(4, 0, 0);
    });
  }

  // Adds entries that occuppy the boundaries (first and last
  // buckets) of the hash table.
  MEMBER_TEST(AddAtBoundaries) {
    // TODO(v8:11330): Remove once CSA implementation has a fallback for
    // non-SSSE3/AVX configurations.
    if (!TestRunner::IsEnabled()) return;
    TS::WithAllInterestingInitialCapacities([](TS& s) {
      AddAtBoundaries(s);

      int capacity = s.initial_capacity;

      std::vector<int> boundary_indices = s.boundary_indices(capacity);
      int size = static_cast<int>(boundary_indices.size());

      int count = 0;
      for (int index : boundary_indices) {
        std::string key = "k" + std::to_string(index);
        std::string value = "v" + std::to_string(index);
        PropertyDetails details = distinct_details(count++);

        s.CheckDataAtKey(Key{key, FakeH1{index + kBigModulus}},
                         InternalIndex(index), value, details);
      }
      s.CheckCounts(capacity, size, 0);
    });
  }

  // Adds entries that occuppy the boundaries of the hash table, then updates
  // their values and property details.
  MEMBER_TEST(UpdateAtBoundaries) {
    // TODO(v8:11330): Remove once CSA implementation has a fallback for
    // non-SSSE3/AVX configurations.
    if (!TestRunner::IsEnabled()) return;
    TS::WithAllInterestingInitialCapacities([](TS& s) {
      AddAtBoundaries(s);

      int capacity = s.initial_capacity;

      std::vector<int> boundary_indices = s.boundary_indices(capacity);
      int size = static_cast<int>(boundary_indices.size());

      int count = 0;
      for (int index : boundary_indices) {
        std::string key = "k" + std::to_string(index);
        std::string value = "newv" + std::to_string(index);
        // setting offset means getting other PropertyDetails than before
        PropertyDetails details = distinct_details(count++, size);

        s.UpdateByKey(Key{key, FakeH1{index + kBigModulus}}, value, details);
      }

      count = 0;
      for (int index : boundary_indices) {
        std::string key = "k" + std::to_string(index);
        std::string value = "newv" + std::to_string(index);
        PropertyDetails details = distinct_details(count++, size);

        s.CheckDataAtKey(Key{key, FakeH1{index + kBigModulus}},
                         InternalIndex(index), value, details);
      }
    });
  }

  // Adds entries that occuppy the boundaries of the hash table, then updates
  // their values and property details.
  MEMBER_TEST(DeleteAtBoundaries) {
    // TODO(v8:11330): Remove once CSA implementation has a fallback for
    // non-SSSE3/AVX configurations.
    if (!TestRunner::IsEnabled()) return;
    // The maximum value of {TS::boundary_indices(capacity).size()} for any
    // |capacity|.
    int count = 4;

    // Due to shrink-on-delete, we create a new dictionary prior to each
    // deletion, so that we don't re-hash (which would defeat the purpose of
    // this test).
    for (int i = 0; i < count; ++i) {
      // In this iteration, we delete the i-th element of |boundary_indices|.

      TS::WithAllInterestingInitialCapacities([&](TS& s) {
        std::vector<int> boundary_indices =
            TS::boundary_indices(s.initial_capacity);
        int number_of_entries = static_cast<int>(boundary_indices.size());
        DCHECK_GE(count, number_of_entries);

        if (i >= static_cast<int>(boundary_indices.size())) {
          // Nothing to do.
          return;
        }

        AddAtBoundaries(s);

        int entry_to_delete = boundary_indices[i];
        int h1 = entry_to_delete + kBigModulus;

        // We know that the key in question was added at bucket
        // |entry_to_delete| by AddAtBoundaries.
        Key key = Key{"k" + std::to_string(entry_to_delete), FakeH1{h1}};
        s.DeleteByKey(key);
        s.CheckKeyAbsent(key);

        // Account for the fact that a shrink-on-delete may have happened.
        int expected_capacity = number_of_entries - 1 < s.initial_capacity / 4
                                    ? s.initial_capacity / 2
                                    : s.initial_capacity;
        s.CheckCounts(expected_capacity, number_of_entries - 1);
      });
    }
  }

  // Adds entries that occuppy the boundaries of the hash table, then add
  // further entries targeting the same buckets.
  MEMBER_TEST(OverwritePresentAtBoundaries) {
    // TODO(v8:11330): Remove once CSA implementation has a fallback for
    // non-SSSE3/AVX configurations.
    if (!TestRunner::IsEnabled()) return;
    TS::WithAllInterestingInitialCapacities([](TS& s) {
      AddAtBoundaries(s);

      int capacity = s.initial_capacity;

      std::vector<int> boundary_indices = s.boundary_indices(capacity);

      std::vector<std::string> keys, values;
      std::vector<PropertyDetails> details;

      int count = 0;
      for (int index : boundary_indices) {
        std::string key = "additional_k" + std::to_string(index);
        std::string value = "additional_v" + std::to_string(index);

        PropertyDetails d = distinct_details(count++);
        keys.push_back(key);
        values.push_back(value);
        details.push_back(d);
        s.Add(Key{key, FakeH1{index + kBigModulus}}, value, d);
      }

      count = 0;
      for (int entry : boundary_indices) {
        std::string key = keys[count];
        std::string value = values[count];
        PropertyDetails d = details[count];

        // We don't know the indices where the new entries will land.
        s.CheckDataAtKey(Key{key, FakeH1{entry + kBigModulus}},
                         base::Optional<InternalIndex>(), value, d);
        count++;
      }

      // The entries added by AddAtBoundaries must also still be there, at their
      // original indices.
      count = 0;
      for (int index : boundary_indices) {
        std::string key = "k" + std::to_string(index);
        std::string value = "v" + std::to_string(index);
        PropertyDetails detail = distinct_property_details.at(count++);
        s.CheckDataAtKey(Key{key, FakeH1{index + kBigModulus}},
                         InternalIndex(index), value, detail);
      }
    });
  }

  MEMBER_TEST(Empty) {
    // TODO(v8:11330): Remove once CSA implementation has a fallback for
    // non-SSSE3/AVX configurations.
    if (!TestRunner::IsEnabled()) return;
    TS::WithInitialCapacities({0}, [](TS& s) {
      // FindEntry on empty table succeeds.
      s.CheckKeyAbsent(Key{"some non-existing key"});
    });

    TS::WithInitialCapacities({0}, [](TS& s) {
      PropertyDetails d = PropertyDetails::Empty();

      // Adding to empty table causes resize.
      s.Add(Key{"some key"}, "some value", d);
      s.CheckDataAtKey(Key{"some key"}, kIndexUnknown, "some value", d);

      s.CheckCounts(SwissNameDictionary::kInitialCapacity, 1, 0);
    });

    TS::WithInitialCapacity(0, [](TS& s) { s.CheckEnumerationOrder({}); });

    // Inplace rehashing and shrinking don't have CSA versions.
    if (TS::IsRuntimeTest()) {
      TS::WithInitialCapacity(0, [](TS& s) {
        s.RehashInplace();
        s.CheckCounts(0, 0, 0);
        s.VerifyHeap();
      });

      TS::WithInitialCapacity(0, [](TS& s) {
        s.Shrink();
        s.CheckCounts(0, 0, 0);
        s.VerifyHeap();
      });
    }
  }

  // We test that hash tables get resized/rehashed correctly by repeatedly
  // adding an deleting elements.
  MEMBER_TEST(Resize1) {
    // TODO(v8:11330): Remove once CSA implementation has a fallback for
    // non-SSSE3/AVX configurations.
    if (!TestRunner::IsEnabled()) return;
    TS::WithInitialCapacity(0, [](TS& s) {
      // Should be at least 8 so that we capture the transition from 8 bit to 16
      // bit meta table entries:
      const int max_exponent = 9;

      // For all |exponent| between 0 and |max_exponent|, we add 2^|exponent|
      // entries, and then delete every second one of those. Note that we do
      // this all on a single table, meaning that the entries from the previous
      // value of |exponent| are still present.
      int added = 0;
      int deleted = 0;
      int offset = 0;
      for (int exponent = 0; exponent <= max_exponent; ++exponent) {
        int count = 1 << exponent;
        for (int i = 0; i < count; ++i) {
          std::string key = "key" + std::to_string(offset + i);
          std::string value = "value" + std::to_string(offset + i);

          s.Add(Key{key}, value, distinct_details(i, offset));
          ++added;
        }
        for (int i = 0; i < count; i += 2) {
          if (offset + i == 0) {
            continue;
          }
          std::string key = "key" + std::to_string(offset + i);
          s.DeleteByKey(Key{key});
          ++deleted;
        }

        s.CheckCounts(kNoInt, added - deleted, kNoInt);
        offset += count;
      }

      // Some internal consistency checks on the test itself:
      DCHECK_EQ((1 << (max_exponent + 1)) - 1, offset);
      DCHECK_EQ(offset, added);
      DCHECK_EQ(offset / 2, deleted);

      // Check that those entries that we expect are indeed present.
      for (int i = 0; i < offset; i += 2) {
        std::string key = "key" + std::to_string(i);
        std::string value = "value" + std::to_string(i);

        s.CheckDataAtKey(Key{key}, kIndexUnknown, value, distinct_details(i));
      }
      s.VerifyHeap();
    });
  }

  // Check that we resize exactly when expected.
  MEMBER_TEST(Resize2) {
    // TODO(v8:11330): Remove once CSA implementation has a fallback for
    // non-SSSE3/AVX configurations.
    if (!TestRunner::IsEnabled()) return;
    TS::WithInitialCapacities({4, 8, 16, 128}, [](TS& s) {
      int count = SwissNameDictionary::MaxUsableCapacity(s.initial_capacity);

      AddMultiple(s, count, "resize2");

      // No resize:
      s.CheckCounts(s.initial_capacity, count, 0);

      s.Add(Key{"key causing resize"});
      s.CheckCounts(2 * s.initial_capacity, count + 1, 0);
    });
  }

  // There are certain capacities where we can fill every single bucket of the
  // table before resizing (i.e., the max load factor is 100% for those
  // particular configurations. Test that this works as intended.
  MEMBER_TEST(AtFullCapacity) {
    // TODO(v8:11330): Remove once CSA implementation has a fallback for
    // non-SSSE3/AVX configurations.
    if (!TestRunner::IsEnabled()) return;
    // Determine those capacities, allowing 100% max load factor. We trust
    // MaxUsableCapacity to tell us which capacities that are (e.g., 4 and 8),
    // because we tested that function separately elsewhere.
    std::vector<int> capacities_allowing_full_utilization;
    for (int c = SwissNameDictionary::kInitialCapacity;
         c <= static_cast<int>(SwissNameDictionary::kGroupWidth); c *= 2) {
      if (SwissNameDictionary::MaxUsableCapacity(c) == c) {
        capacities_allowing_full_utilization.push_back(c);
      }
    }

    DCHECK_IMPLIES(SwissNameDictionary::kGroupWidth == 16,
                   capacities_allowing_full_utilization.size() > 0);

    TS::WithInitialCapacities(capacities_allowing_full_utilization, [](TS& s) {
      AddMultiple(s, s.initial_capacity, "k_full_capacity", "v_full_capacity");

      // No resize must have happened.
      s.CheckCounts(s.initial_capacity, s.initial_capacity, 0);

      CheckMultiple(s, s.initial_capacity, "k_full_capacity",
                    "v_full_capacity");

      // Must make sure that the first |SwissNameDictionary::kGroupWidth|
      // entries of the ctrl table contain a kEmpty, so that an unsuccessful
      // search stop, instead of going into an infinite loop. Therefore, search
      // for a fake key whose H1 is 0, making us start from ctrl table bucket 0.
      s.CheckKeyAbsent(Key{"non_existing_key", FakeH1{0}, FakeH2{1}});
    });
  }

  MEMBER_TEST(EnumerationOrder) {
    // TODO(v8:11330) Disabling this for now until the real CSA testing has
    // landed.
    if (true) return;

    // This test times out on sanitizer builds in CSA mode when testing the
    // larger capacities.
    // TODO(v8:11330) Revisit this once the actual CSA/Torque versions are run
    // by the test suite, which will speed things up.
    std::vector<int> capacities_to_test =
        TS::IsRuntimeTest() ? interesting_initial_capacities
                            : capacities_for_slow_sanitizer_tests;

    TS::WithInitialCapacities(capacities_to_test, [](TS& s) {
      std::vector<std::string> expected_keys;
      int count = std::min(
          SwissNameDictionary::MaxUsableCapacity(s.initial_capacity), 1000);

      for (int i = 0; i < count; ++i) {
        std::string key = "enumkey" + std::to_string(i);
        expected_keys.push_back(key);
        s.Add(Key{key});
      }
      s.CheckEnumerationOrder(expected_keys);

      // Delete some entries.

      std::string last_key = "enumkey" + std::to_string(count - 1);
      s.DeleteByKey(Key{"enumkey0"});
      s.DeleteByKey(Key{"enumkey1"});
      s.DeleteByKey(Key{last_key});

      auto should_be_deleted = [&](const std::string& k) -> bool {
        return k == "enumkey0" || k == "enumkey1" || k == last_key;
      };
      expected_keys.erase(
          std::remove_if(expected_keys.begin(), expected_keys.end(),
                         should_be_deleted),
          expected_keys.end());
      DCHECK_EQ(expected_keys.size(), count - 3);

      s.CheckEnumerationOrder(expected_keys);

      if (s.initial_capacity <= 1024) {
        // Now cause a resize. Doing + 4 on top of the maximum usable capacity
        // rather than just + 1 because in the case where the initial capacity
        // is 4 and the group size is 8, the three deletes above caused a
        // shrink, which in this case was just a rehash. So we need to add 4
        // elements to cause a resize.
        int resize_at =
            SwissNameDictionary::MaxUsableCapacity(s.initial_capacity) + 4;

        for (int i = count; i < resize_at; ++i) {
          std::string key = "enumkey" + std::to_string(i);
          expected_keys.push_back(key);
          s.Add(Key{key});
        }
        s.CheckCounts(2 * s.initial_capacity);
        s.CheckEnumerationOrder(expected_keys);
      }
    });
  }

  // Make sure that keys with colliding H1 and same H2 don't get mixed up.
  MEMBER_TEST(SameH2) {
    // TODO(v8:11330): Remove once CSA implementation has a fallback for
    // non-SSSE3/AVX configurations.
    if (!TestRunner::IsEnabled()) return;
    int i = 0;
    TS::WithAllInterestingInitialCapacities([&](TS& s) {
      // Let's try a few differnet values for h1, starting at big_modulus;.
      int first_h1 = i * 13 + kBigModulus;
      int second_h1 = first_h1 + s.initial_capacity;

      int first_entry = first_h1 % s.initial_capacity;
      int second_entry = (first_h1 + 1) % s.initial_capacity;

      // Add two keys with same H1 modulo capacity and same H2.
      Key k1{"first_key", FakeH1{first_h1}, FakeH2{42}};
      Key k2{"second_key", FakeH1{second_h1}, FakeH2{42}};

      s.Add(k1, "v1");
      s.Add(k2, "v2");

      s.CheckDataAtKey(k1, InternalIndex(first_entry), "v1");
      s.CheckDataAtKey(k2, InternalIndex(second_entry), "v2");

      // Deletion works, too.
      s.DeleteByKey(k2);
      s.CheckHasKey(k1);
      s.CheckKeyAbsent(k2);

      ++i;
    });
  }

  // Check that we can delete a key and add it again.
  MEMBER_TEST(ReAddSameKey) {
    // TODO(v8:11330): Remove once CSA implementation has a fallback for
    // non-SSSE3/AVX configurations.
    if (!TestRunner::IsEnabled()) return;
    TS::WithInitialCapacity(4, [](TS& s) {
      s.Add(Key{"some_key"}, "some_value", distinct_details(0));
      s.DeleteByKey(Key{"some_key"});
      s.Add(Key{"some_key"}, "new_value", distinct_details(1));
      s.CheckDataAtKey(Key{"some_key"}, kIndexUnknown, "new_value",
                       distinct_details(1));
      s.CheckEnumerationOrder({"some_key"});
    });
  }

  // Make sure that we continue probing if there is no match in the first
  // group and that the quadratic probing for choosing subsequent groups to
  // probe works as intended.
  MEMBER_TEST(BeyondInitialGroup) {
    // TODO(v8:11330): Remove once CSA implementation has a fallback for
    // non-SSSE3/AVX configurations.
    if (!TestRunner::IsEnabled()) return;
    TS::WithInitialCapacity(128, [](TS& s) {
      int h1 = 33;     // Arbitrarily chosen.
      int count = 37;  // Will lead to more than 2 groups being filled.

      for (int i = 0; i < count; ++i) {
        std::string key = "key" + std::to_string(i);
        std::string value = "value" + std::to_string(i);

        s.Add(Key{key, FakeH1{h1}}, value);
      }

      s.CheckDataAtKey(Key{"key36", FakeH1{h1}}, kIndexUnknown, "value36");

      // Deleting something shouldn't disturb further additions.
      s.DeleteByKey(Key{"key14", FakeH1{h1}});
      s.DeleteByKey(Key{"key15", FakeH1{h1}});
      s.DeleteByKey(Key{"key16", FakeH1{h1}});
      s.DeleteByKey(Key{"key17", FakeH1{h1}});

      s.Add(Key{"key37", FakeH1{h1}}, "value37");
      s.CheckDataAtKey(Key{"key37", FakeH1{h1}}, kIndexUnknown, "value37");
    });
  }

  // Check that we correclty "wrap around" when probing the control table. This
  // means that when we probe a group starting at a bucket such that there are
  // fewer than kGroupWidth bucktets before the end of the control table, we
  // (logically) continue at bucket 0. Note that actually, we use the copy of
  // first group at the end of the control table.
  MEMBER_TEST(WrapAround) {
    // TODO(v8:11330) Disabling this for now until the real CSA testing has
    // landed.
    if (true) {
      return;
    }

    // This test times out in CSA mode when testing the larger capacities.
    // TODO(v8:11330) Revisit this once the actual CSA/Torque versions are run
    // by the test suite, which will speed things up.
    std::vector<int> capacities_to_test = TS::IsRuntimeTest()
                                              ? interesting_initial_capacities
                                              : capacities_for_slow_debug_tests;

    int width = SwissNameDictionary::kGroupWidth;
    for (int offset_from_end = 0; offset_from_end < width; ++offset_from_end) {
      TS::WithInitialCapacities(capacities_to_test, [&](TS& s) {
        int capacity = s.initial_capacity;
        int first_bucket = capacity - offset_from_end;

        // How many entries to add (carefully chosen not to cause a resize).
        int filler_entries =
            std::min(width, SwissNameDictionary::MaxUsableCapacity(capacity)) -
            1;

        if (first_bucket < 0 ||
            // No wraparound in this case:
            first_bucket + filler_entries < capacity) {
          return;
        }

        // Starting at bucket |first_bucket|, add a sequence of |kGroupWitdth|
        // - 1 (if table can take that many, see calculation of |filler_entries|
        // above) entries in a single collision chain.
        for (int f = 0; f < filler_entries; ++f) {
          std::string key = "filler" + std::to_string(f);
          s.Add(Key{key, FakeH1{first_bucket}});
        }

        // ... then add a final key which (unless table too small) will end up
        // in the last bucket belonging to the group started at |first_bucket|.
        // Check that we can indeed find it.
        s.Add(Key{"final_key", FakeH1{first_bucket}});
        s.CheckDataAtKey(Key{"final_key", FakeH1{first_bucket}},
                         InternalIndex(filler_entries - offset_from_end));

        // + 1 due to the final key.
        s.CheckCounts(s.initial_capacity, filler_entries + 1, 0);

        // Now delete the entries in between and make sure that this
        // doesn't break anything.
        for (int f = 0; f < filler_entries; ++f) {
          std::string key = "filler" + std::to_string(f);
          s.DeleteByKey(Key{key, FakeH1{first_bucket}});
        }

        s.CheckHasKey(Key{"final_key", FakeH1{first_bucket}});
      });
    }
  }

  MEMBER_TEST(RehashInplace) {
    // This test may fully fill the table and hardly depends on the underlying
    // shape (e.g., meta table structure). Thus not testing overly large
    // capacities.
    std::vector<int> capacities_to_test = {4, 8, 16, 128, 1024};
    if (TS::IsRuntimeTest()) {
      TS::WithInitialCapacities(capacities_to_test, [](TS& s) {
        if (s.initial_capacity <= 8) {
          // Add 3 elements, which will not cause a resize. Then delete the
          // first key before rehasing.

          AddMultiple(s, 3);
          s.DeleteByKey(Key{"key0"});

          // We shouldn't have done a resize on deletion or addition:
          s.CheckCounts(s.initial_capacity, 2, 1);

          s.RehashInplace();

          s.CheckDataAtKey(Key{"key1"}, kIndexUnknown, "value1");
          s.CheckDataAtKey(Key{"key2"}, kIndexUnknown, "value2");
          s.CheckEnumerationOrder({"key1", "key2"});
        } else {
          int count =
              SwissNameDictionary::MaxUsableCapacity(s.initial_capacity) - 5;
          AddMultiple(s, count);

          s.DeleteByKey(Key{"key1"});
          s.DeleteByKey(Key{"key2"});
          s.DeleteByKey(Key{"key" + std::to_string(count - 1)});

          // We shouldn't have done a resize on deletion or addition:
          s.CheckCounts(s.initial_capacity, count - 3, 3);

          s.RehashInplace();

          std::vector<std::string> expected_enum_order;
          for (int i = 0; i < count; ++i) {
            if (i == 1 || i == 2 || i == count - 1) {
              // These are the keys we deleted.
              continue;
            }

            std::string key = "key" + std::to_string(i);
            PropertyDetails d =
                distinct_property_details[i % distinct_property_details.size()];
            s.CheckDataAtKey(Key{key}, kIndexUnknown,
                             "value" + std::to_string(i), d);

            expected_enum_order.push_back(key);
          }

          s.CheckEnumerationOrder(expected_enum_order);
        }
      });
    }
  }

  MEMBER_TEST(Shrink) {
    if (TS::IsRuntimeTest()) {
      TS::WithInitialCapacity(32, [&](TS& s) {
        // Filling less than a forth of the table:
        int count = 4;

        AddMultiple(s, count);

        s.Shrink();

        CheckMultiple(s, count, "key", "value", 0);

        // Shrink doesn't shrink to fit, but only halves the capacity.
        int expected_capacity = s.initial_capacity / 2;
        s.CheckCounts(expected_capacity, 4, 0);

        s.CheckEnumerationOrder({"key0", "key1", "key2", "key3"});
        s.VerifyHeap();
      });
    }
  }

  MEMBER_TEST(ShrinkToInitial) {
    // When shrinking, we never go below SwissNameDictionary::kInitialCapacity.
    if (TS::IsRuntimeTest()) {
      TS::WithInitialCapacity(8, [&](TS& s) {
        s.Shrink();

        s.CheckCounts(SwissNameDictionary::kInitialCapacity, 0, 0);
      });
    }
  }

  MEMBER_TEST(ShrinkOnDelete) {
    // TODO(v8:11330): Remove once CSA implementation has a fallback for
    // non-SSSE3/AVX configurations.
    if (!TestRunner::IsEnabled()) return;
    TS::WithInitialCapacity(32, [](TS& s) {
      // Adds key0 ... key9:
      AddMultiple(s, 10);

      // We remove some entries. Each time less than a forth of the table is
      // used by present entries, it's shrunk to half.

      s.DeleteByKey(Key{"key9"});
      s.DeleteByKey(Key{"key8"});

      s.CheckCounts(32, 8, 2);

      s.DeleteByKey(Key{"key7"});

      // Deleted count is 0 after rehash.
      s.CheckCounts(16, 7, 0);
    });
  }

  MEMBER_TEST(Copy) {
    // TODO(v8:11330) Disabling this for now until the real CSA testing has
    // landed.
    if (true) return;

    // This test times out on sanitizer builds in CSA mode when testing the
    // larger capacities.
    // TODO(v8:11330) Revisit this once the actual CSA/Torque versions are run
    // by the test suite, which will speed things up.
    std::vector<int> capacities_to_test =
        TS::IsRuntimeTest() ? interesting_initial_capacities
                            : capacities_for_slow_sanitizer_tests;
    TS::WithInitialCapacities(capacities_to_test, [](TS& s) {
      int fill = std::min(
          1000,
          // -2 due to the two manually added keys below.
          SwissNameDictionary::MaxUsableCapacity(s.initial_capacity) - 2);
      AddMultiple(s, fill);

      // Occupy first and last bucket (another key may occuppy these already,
      // but let's don't bother with that):
      s.Add(Key{"first_bucket_key", FakeH1{kBigModulus}});
      s.Add(Key{"last_bucket_key", FakeH1{s.initial_capacity - 1}});

      // We shouldn't have caused a resize.
      s.CheckCounts(s.initial_capacity);

      // Creates a copy and compares it against the original. In order to check
      // copying of large dictionary, need to check before deletion due to
      // shrink-on-delete kicking in.
      s.CheckCopy();

      // Let's delete a few entries, most notably the first and last two in enum
      // order and the keys (potentially) occupying the first and last bucket.
      s.DeleteByKey(Key{"key0"});
      if (fill > 1) {
        s.DeleteByKey(Key{"key1"});
      }
      s.DeleteByKey(Key{"first_bucket_key", FakeH1{kBigModulus}});
      s.DeleteByKey(Key{"last_bucket_key", FakeH1{s.initial_capacity - 1}});

      s.CheckCopy();
    });
  }
};

}  // namespace test_swiss_hash_table
}  // namespace internal
}  // namespace v8

#endif  // V8_TEST_CCTEST_TEST_SWISS_HASH_TABLE_SHARED_TESTS_H_