//===--- Metadata.cpp - Metadata tests ------------------------------------===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See https://swift.org/LICENSE.txt for license information
// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
//
//===----------------------------------------------------------------------===//

#include "swift/Runtime/Metadata.h"
#include "swift/Runtime/HeapObject.h"
#include "swift/Runtime/Concurrent.h"
#include "swift/Runtime/Once.h"
#include "gtest/gtest.h"
#include <iterator>
#include <functional>
#include <vector>
#include <thread>
#include <condition_variable>

#if SWIFT_OBJC_INTEROP
#include <objc/runtime.h>
#endif

using namespace swift;

#if false
// Race testing.

template <typename T>
struct RaceThreadContext {
  std::function<T()> code;
  T result;

  unsigned numThreads;
  unsigned &numThreadsReady;
  std::mutex &sharedMutex;
  std::condition_variable &start_condition;
};

template <typename T>
void RaceThunk(RaceThreadContext<T> &ctx) {
  // update shared state
  std::unique_lock<std::mutex> lk(ctx.sharedMutex);
  ++ctx.numThreadsReady;
  bool isLastThread = ctx.numThreadsReady == ctx.numThreads;

  // wait until the rest of the thunks are ready
  ctx.start_condition.wait(lk, [&ctx]{ // waiting releases the lock
    return ctx.numThreadsReady == ctx.numThreads;
  });
  lk.unlock();

  // The last thread will signal the condition_variable to kick off the rest
  // of the waiting threads to start.
  if (isLastThread) ctx.start_condition.notify_all();

  ctx.result = ctx.code();
}

/// RaceTest(code) runs code in many threads simultaneously,
/// and returns a vector of all returned results.
template <typename T, unsigned NumThreads = 64>
std::vector<T> RaceTest(std::function<T()> code) {
  unsigned numThreadsReady = 0;
  std::mutex sharedMutex;
  std::condition_variable start_condition;
  T result = NULL;

  // Create the contexts
  std::vector<RaceThreadContext<T>> contexts(NumThreads, {
		  code,
		  result,
		  NumThreads,
		  numThreadsReady,
		  sharedMutex,
		  start_condition});

  // Create the threads
  std::vector<std::thread> threads;
  threads.reserve(NumThreads);
  for (unsigned i = 0; i < NumThreads; i++)
    threads.emplace_back(std::bind(RaceThunk<T>, std::ref(contexts[i])));

  // Collect results.
  std::vector<T> results;
  results.reserve(NumThreads);
  for (unsigned i = 0; i < NumThreads; i++) {
    threads[i].join();
    results.emplace_back(contexts[i].result);
  }
  return results;
}

/// RaceTest_ExpectEqual(code) runs code in many threads simultaneously,
/// verifies that they all returned the same value, and returns that value.
template<typename T>
T RaceTest_ExpectEqual(std::function<T()> code)
{
  auto results = RaceTest<T>(code);
  auto r0 = results[0];
  for (auto r : results) {
    EXPECT_EQ(r0, r);
  }

  return r0;
}

/// Some unique global pointers.
uint32_t Global1 = 0;
uint32_t Global2 = 0;
uint32_t Global3 = 0;

struct TestObjContainer {
  swift_once_t token;
  HeapObject obj;
};

TestObjContainer StaticTestObj;
HeapMetadata StaticTestMD;

TEST(StaticObjects, ini) {
  RaceTest_ExpectEqual<const Metadata *>(
     [&]() -> const Metadata * {
       // Check if the object header is initialized once.
       HeapObject *o = swift_initStaticObject(&StaticTestMD, &StaticTestObj.obj);
       EXPECT_EQ(o, &StaticTestObj.obj);
       EXPECT_EQ(StaticTestObj.obj.metadata, &StaticTestMD);
#ifdef __APPLE__
       EXPECT_NE(StaticTestObj.token, 0);
#endif
       const int NumRcOps = 1000;
       for (int i = 0; i < NumRcOps; i++) {
         swift_retain(&StaticTestObj.obj);
       }
       for (int i = 0; i < NumRcOps; i++) {
         swift_release(&StaticTestObj.obj);
       }
       return StaticTestObj.obj.metadata;
     });
  EXPECT_EQ(swift_retainCount(&StaticTestObj.obj), 1u);
}

FullMetadata<ClassMetadata> MetadataTest2 = {
  { { nullptr }, { &VALUE_WITNESS_SYM(Bo) } },
  { { nullptr }, ClassFlags(), 0, 0, 0, 0, 0, 0 }
};

TEST(MetadataTest, getMetatypeMetadata) {
  auto inst1 = RaceTest_ExpectEqual<const MetatypeMetadata *>(
    [&]() -> const MetatypeMetadata * {
      auto inst = swift_getMetatypeMetadata(&METADATA_SYM(Bi64_).base);

      EXPECT_EQ(sizeof(void*), inst->getValueWitnesses()->size);
      return inst;
    });

  auto inst2 = RaceTest_ExpectEqual<const MetatypeMetadata *>(
    [&]() -> const MetatypeMetadata * {
      auto inst = swift_getMetatypeMetadata(&METADATA_SYM(Bi32_).base);

      EXPECT_EQ(sizeof(void*), inst->getValueWitnesses()->size);
      return inst;
    });

  auto inst3 = RaceTest_ExpectEqual<const MetatypeMetadata *>(
    [&]() -> const MetatypeMetadata * {
      auto inst = swift_getMetatypeMetadata(&MetadataTest2);

      EXPECT_EQ(sizeof(void*), inst->getValueWitnesses()->size);
      return inst;
    });

  auto inst4 = RaceTest_ExpectEqual<const MetatypeMetadata *>(
    [&]() -> const MetatypeMetadata * {
      auto inst = swift_getMetatypeMetadata(inst3);
      EXPECT_EQ(sizeof(void*), inst->getValueWitnesses()->size);
      return inst;
    });

  auto inst5 = RaceTest_ExpectEqual<const MetatypeMetadata *>(
    [&]() -> const MetatypeMetadata * {
      auto inst = swift_getMetatypeMetadata(inst1);
      EXPECT_EQ(sizeof(void*), inst->getValueWitnesses()->size);
      return inst;
    });

  // After all this, the instance type fields should still be valid.
  ASSERT_EQ(&METADATA_SYM(Bi64_).base, inst1->InstanceType);
  ASSERT_EQ(&METADATA_SYM(Bi32_).base, inst2->InstanceType);
  ASSERT_EQ(&MetadataTest2, inst3->InstanceType);
  ASSERT_EQ(inst3, inst4->InstanceType);
  ASSERT_EQ(inst1, inst5->InstanceType);
}

ProtocolDescriptor ProtocolA{
  "_TMp8Metadata9ProtocolA",
  nullptr,
  ProtocolDescriptorFlags()
    .withSwift(true)
    .withClassConstraint(ProtocolClassConstraint::Any)
    .withDispatchStrategy(ProtocolDispatchStrategy::Swift)
};

ProtocolDescriptor ProtocolB{
  "_TMp8Metadata9ProtocolB",
  nullptr,
  ProtocolDescriptorFlags()
    .withSwift(true)
    .withClassConstraint(ProtocolClassConstraint::Any)
    .withDispatchStrategy(ProtocolDispatchStrategy::Swift)
};

ProtocolDescriptor ProtocolError{
  "_TMp8Metadata13ProtocolError",
  nullptr,
  ProtocolDescriptorFlags()
    .withSwift(true)
    .withClassConstraint(ProtocolClassConstraint::Any)
    .withDispatchStrategy(ProtocolDispatchStrategy::Swift)
    .withSpecialProtocol(SpecialProtocol::Error)
};

ProtocolDescriptor ProtocolClassConstrained{
  "_TMp8Metadata24ProtocolClassConstrained",
  nullptr,
  ProtocolDescriptorFlags()
    .withSwift(true)
    .withClassConstraint(ProtocolClassConstraint::Class)
    .withDispatchStrategy(ProtocolDispatchStrategy::Swift)
};

TEST(MetadataTest, getExistentialMetadata) {
  RaceTest_ExpectEqual<const ExistentialTypeMetadata *>(
    [&]() -> const ExistentialTypeMetadata * {
      auto any = swift_getExistentialTypeMetadata(ProtocolClassConstraint::Any,
                                                  /*superclass=*/nullptr,
                                                  0, nullptr);
      EXPECT_EQ(MetadataKind::Existential, any->getKind());
      EXPECT_EQ(0U, any->Flags.getNumWitnessTables());
      EXPECT_EQ(ProtocolClassConstraint::Any, any->Flags.getClassConstraint());
      EXPECT_EQ(0U, any->NumProtocols);
      EXPECT_EQ(SpecialProtocol::None,
                any->Flags.getSpecialProtocol());
      EXPECT_EQ(nullptr,
                any->getSuperclassConstraint());
      return any;
    });

  ProtocolDescriptorRef protoList2[] = {
    ProtocolDescriptorRef::forSwift(&ProtocolA)
  };
  auto exA = RaceTest_ExpectEqual<const ExistentialTypeMetadata *>(
    [&]() -> const ExistentialTypeMetadata * {
      auto a = swift_getExistentialTypeMetadata(ProtocolClassConstraint::Any,
                                                /*superclass=*/nullptr,
                                                1, protoList2);
      EXPECT_EQ(MetadataKind::Existential, a->getKind());
      EXPECT_EQ(1U, a->Flags.getNumWitnessTables());
      EXPECT_EQ(ProtocolClassConstraint::Any, a->Flags.getClassConstraint());
      EXPECT_EQ(1U, a->NumProtocols);
      EXPECT_EQ(&ProtocolA, a->getProtocols()[0].getSwiftProtocol());
      EXPECT_EQ(SpecialProtocol::None,
                a->Flags.getSpecialProtocol());
      EXPECT_EQ(nullptr,
                a->getSuperclassConstraint());
      return a;
    });

  ProtocolDescriptorRef protoList3[] = {
    ProtocolDescriptorRef::forSwift(&ProtocolB)
  };
  RaceTest_ExpectEqual<const ExistentialTypeMetadata *>(
    [&]() -> const ExistentialTypeMetadata * {
      auto b = swift_getExistentialTypeMetadata(ProtocolClassConstraint::Any,
                                                /*superclass=*/nullptr,
                                                1, protoList3);
      EXPECT_NE(exA, b);
      EXPECT_EQ(MetadataKind::Existential, b->getKind());
      EXPECT_EQ(1U, b->Flags.getNumWitnessTables());
      EXPECT_EQ(ProtocolClassConstraint::Any, b->Flags.getClassConstraint());
      EXPECT_EQ(1U, b->NumProtocols);
      EXPECT_EQ(&ProtocolB, b->getProtocols()[0].getSwiftProtocol());
      EXPECT_EQ(SpecialProtocol::None,
                b->Flags.getSpecialProtocol());
      EXPECT_EQ(nullptr,
                b->getSuperclassConstraint());
      return b;
    });

  ProtocolDescriptorRef protoList6[] = {
    ProtocolDescriptorRef::forSwift(&ProtocolClassConstrained)
  };
  RaceTest_ExpectEqual<const ExistentialTypeMetadata *>(
    [&]() -> const ExistentialTypeMetadata * {
      auto classConstrained
        = swift_getExistentialTypeMetadata(ProtocolClassConstraint::Class,
                                           /*superclass=*/nullptr,
                                           1, protoList6);
      EXPECT_EQ(MetadataKind::Existential, classConstrained->getKind());
      EXPECT_EQ(1U, classConstrained->Flags.getNumWitnessTables());
      EXPECT_EQ(ProtocolClassConstraint::Class,
                classConstrained->Flags.getClassConstraint());
      EXPECT_EQ(1U, classConstrained->NumProtocols);
      EXPECT_EQ(SpecialProtocol::None,
                classConstrained->Flags.getSpecialProtocol());
      EXPECT_EQ(&ProtocolClassConstrained,
                classConstrained->getProtocols()[0].getSwiftProtocol());
      EXPECT_EQ(nullptr,
                classConstrained->getSuperclassConstraint());
      return classConstrained;
    });

#if SWIFT_OBJC_INTEROP
#define EXAMPLE_OBJC_PROTOCOL_NAME "NSCopying"

  ProtocolDescriptorRef protoList7[] = {
    ProtocolDescriptorRef::forObjC(objc_getProtocol(EXAMPLE_OBJC_PROTOCOL_NAME))
  };
  RaceTest_ExpectEqual<const ExistentialTypeMetadata *>(
    [&]() -> const ExistentialTypeMetadata * {
      auto noWitnessTable
        = swift_getExistentialTypeMetadata(ProtocolClassConstraint::Class,
                                           /*superclass=*/nullptr,
                                           1, protoList7);
      EXPECT_EQ(MetadataKind::Existential, noWitnessTable->getKind());
      EXPECT_EQ(0U, noWitnessTable->Flags.getNumWitnessTables());
      EXPECT_EQ(ProtocolClassConstraint::Class,
                noWitnessTable->Flags.getClassConstraint());
      EXPECT_EQ(1U, noWitnessTable->NumProtocols);
      EXPECT_EQ(SpecialProtocol::None,
                noWitnessTable->Flags.getSpecialProtocol());
      EXPECT_EQ(objc_getProtocol(EXAMPLE_OBJC_PROTOCOL_NAME),
                noWitnessTable->getProtocols()[0].getObjCProtocol());
      EXPECT_EQ(nullptr,
                noWitnessTable->getSuperclassConstraint());
      return noWitnessTable;
    });

  RaceTest_ExpectEqual<const ExistentialTypeMetadata *>(
    [&]() -> const ExistentialTypeMetadata * {
      ProtocolDescriptorRef protoList8[] = {
        ProtocolDescriptorRef::forObjC(
            objc_getProtocol(EXAMPLE_OBJC_PROTOCOL_NAME)),
        ProtocolDescriptorRef::forSwift(&ProtocolA),
        ProtocolDescriptorRef::forSwift(&ProtocolB)
      };

      auto mixedWitnessTable
        = swift_getExistentialTypeMetadata(ProtocolClassConstraint::Class,
                                           /*superclass=*/nullptr,
                                           3, protoList8);
      EXPECT_EQ(MetadataKind::Existential, mixedWitnessTable->getKind());
      EXPECT_EQ(2U, mixedWitnessTable->Flags.getNumWitnessTables());
      EXPECT_EQ(ProtocolClassConstraint::Class,
                mixedWitnessTable->Flags.getClassConstraint());
      EXPECT_EQ(3U, mixedWitnessTable->NumProtocols);
      EXPECT_EQ(SpecialProtocol::None,
                mixedWitnessTable->Flags.getSpecialProtocol());
      EXPECT_EQ(nullptr,
                mixedWitnessTable->getSuperclassConstraint());
      return mixedWitnessTable;
    });
#endif

  const ValueWitnessTable *ExpectedErrorValueWitnesses;
#if SWIFT_OBJC_INTEROP
  ExpectedErrorValueWitnesses = &VALUE_WITNESS_SYM(BO);
#else
  ExpectedErrorValueWitnesses = &VALUE_WITNESS_SYM(Bo);
#endif

  ProtocolDescriptorRef protoList9[] = {
    ProtocolDescriptorRef::forSwift(&ProtocolError)
  };
  RaceTest_ExpectEqual<const ExistentialTypeMetadata *>(
    [&]() -> const ExistentialTypeMetadata * {
      auto special
        = swift_getExistentialTypeMetadata(ProtocolClassConstraint::Any,
                                           /*superclass=*/nullptr,
                                           1, protoList9);
      EXPECT_EQ(MetadataKind::Existential, special->getKind());
      EXPECT_EQ(1U, special->Flags.getNumWitnessTables());
      EXPECT_EQ(SpecialProtocol::Error,
                special->Flags.getSpecialProtocol());
      EXPECT_EQ(ExpectedErrorValueWitnesses,
                special->getValueWitnesses());
      EXPECT_EQ(nullptr,
                special->getSuperclassConstraint());
      return special;
    });

  RaceTest_ExpectEqual<const ExistentialTypeMetadata *>(
    [&]() -> const ExistentialTypeMetadata * {
      ProtocolDescriptorRef protoList10[] = {
        ProtocolDescriptorRef::forSwift(&ProtocolError),
        ProtocolDescriptorRef::forSwift(&ProtocolA)
      };

      auto special
        = swift_getExistentialTypeMetadata(ProtocolClassConstraint::Any,
                                           /*superclass=*/nullptr,
                                           2, protoList10);
      EXPECT_EQ(MetadataKind::Existential, special->getKind());
      EXPECT_EQ(2U, special->Flags.getNumWitnessTables());
      // Compositions of special protocols aren't special.
      EXPECT_EQ(SpecialProtocol::None,
                special->Flags.getSpecialProtocol());
      EXPECT_NE(ExpectedErrorValueWitnesses,
                special->getValueWitnesses());
      EXPECT_EQ(nullptr,
                special->getSuperclassConstraint());
      return special;
    });
}

static ProtocolDescriptor OpaqueProto1 = { "OpaqueProto1", nullptr,
  ProtocolDescriptorFlags().withSwift(true)
                          .withDispatchStrategy(ProtocolDispatchStrategy::Swift)
                          .withClassConstraint(ProtocolClassConstraint::Any)
};
static ProtocolDescriptor OpaqueProto2 = { "OpaqueProto2", nullptr,
  ProtocolDescriptorFlags().withSwift(true)
                          .withDispatchStrategy(ProtocolDispatchStrategy::Swift)
                          .withClassConstraint(ProtocolClassConstraint::Any)
};
static ProtocolDescriptor OpaqueProto3 = { "OpaqueProto3", nullptr,
  ProtocolDescriptorFlags().withSwift(true)
                          .withDispatchStrategy(ProtocolDispatchStrategy::Swift)
                          .withClassConstraint(ProtocolClassConstraint::Any)
};
static ProtocolDescriptor ClassProto1 = { "ClassProto1", nullptr,
  ProtocolDescriptorFlags().withSwift(true)
                          .withDispatchStrategy(ProtocolDispatchStrategy::Swift)
                          .withClassConstraint(ProtocolClassConstraint::Class)
};

TEST(MetadataTest, getExistentialTypeMetadata_opaque) {
  ProtocolDescriptorRef protoList1[] = {
    ProtocolDescriptorRef::forSwift(&OpaqueProto1)
  };
  RaceTest_ExpectEqual<const ExistentialTypeMetadata *>(
    [&]() -> const ExistentialTypeMetadata * {
      auto ex1 = swift_getExistentialTypeMetadata(ProtocolClassConstraint::Any,
                                                  /*superclass=*/nullptr,
                                                  1, protoList1);
      EXPECT_EQ(MetadataKind::Existential, ex1->getKind());
      EXPECT_EQ(5 * sizeof(void*), ex1->getValueWitnesses()->getSize());
      EXPECT_EQ(alignof(void*), ex1->getValueWitnesses()->getAlignment());
      EXPECT_FALSE(ex1->getValueWitnesses()->isPOD());
      EXPECT_TRUE(ex1->getValueWitnesses()->isBitwiseTakable());
      EXPECT_EQ(nullptr,
                ex1->getSuperclassConstraint());
      return ex1;
    });

  ProtocolDescriptorRef protoList2[] = {
    ProtocolDescriptorRef::forSwift(&OpaqueProto1),
    ProtocolDescriptorRef::forSwift(&OpaqueProto2)
  };
  RaceTest_ExpectEqual<const ExistentialTypeMetadata *>(
    [&]() -> const ExistentialTypeMetadata * {
      auto ex2 = swift_getExistentialTypeMetadata(ProtocolClassConstraint::Any,
                                                  /*superclass=*/nullptr,
                                                  2, protoList2);
      EXPECT_EQ(MetadataKind::Existential, ex2->getKind());
      EXPECT_EQ(6 * sizeof(void*), ex2->getValueWitnesses()->getSize());
      EXPECT_EQ(alignof(void*), ex2->getValueWitnesses()->getAlignment());
      EXPECT_FALSE(ex2->getValueWitnesses()->isPOD());
      EXPECT_TRUE(ex2->getValueWitnesses()->isBitwiseTakable());
      EXPECT_EQ(nullptr,
                ex2->getSuperclassConstraint());
      return ex2;
    });

  ProtocolDescriptorRef protoList3[] = {
    ProtocolDescriptorRef::forSwift(&OpaqueProto1),
    ProtocolDescriptorRef::forSwift(&OpaqueProto2),
    ProtocolDescriptorRef::forSwift(&OpaqueProto3)
  };
  RaceTest_ExpectEqual<const ExistentialTypeMetadata *>(
    [&]() -> const ExistentialTypeMetadata * {
      auto ex3 = swift_getExistentialTypeMetadata(ProtocolClassConstraint::Any,
                                                  /*superclass=*/nullptr,
                                                  3, protoList3);
      EXPECT_EQ(MetadataKind::Existential, ex3->getKind());
      EXPECT_EQ(7 * sizeof(void*), ex3->getValueWitnesses()->getSize());
      EXPECT_EQ(alignof(void*), ex3->getValueWitnesses()->getAlignment());
      EXPECT_FALSE(ex3->getValueWitnesses()->isPOD());
      EXPECT_TRUE(ex3->getValueWitnesses()->isBitwiseTakable());
      EXPECT_EQ(nullptr,
                ex3->getSuperclassConstraint());
      return ex3;
    });
}

TEST(MetadataTest, getExistentialTypeMetadata_class) {
  ProtocolDescriptorRef protoList1[] = {
    ProtocolDescriptorRef::forSwift(&ClassProto1)
  };
  RaceTest_ExpectEqual<const ExistentialTypeMetadata *>(
    [&]() -> const ExistentialTypeMetadata * {
      auto ex1 = swift_getExistentialTypeMetadata(ProtocolClassConstraint::Class,
                                                  /*superclass=*/nullptr,
                                                  1, protoList1);
      EXPECT_EQ(MetadataKind::Existential, ex1->getKind());
      EXPECT_EQ(2 * sizeof(void*), ex1->getValueWitnesses()->getSize());
      EXPECT_EQ(alignof(void*), ex1->getValueWitnesses()->getAlignment());
      EXPECT_FALSE(ex1->getValueWitnesses()->isPOD());
      EXPECT_TRUE(ex1->getValueWitnesses()->isBitwiseTakable());
      EXPECT_EQ(nullptr,
                ex1->getSuperclassConstraint());
      return ex1;
    });

  ProtocolDescriptorRef protoList2[] = {
    ProtocolDescriptorRef::forSwift(&OpaqueProto1),
    ProtocolDescriptorRef::forSwift(&ClassProto1)
  };
  RaceTest_ExpectEqual<const ExistentialTypeMetadata *>(
    [&]() -> const ExistentialTypeMetadata * {
      auto ex2 = swift_getExistentialTypeMetadata(ProtocolClassConstraint::Class,
                                                  /*superclass=*/nullptr,
                                                  2, protoList2);
      EXPECT_EQ(MetadataKind::Existential, ex2->getKind());
      EXPECT_EQ(3 * sizeof(void*), ex2->getValueWitnesses()->getSize());
      EXPECT_EQ(alignof(void*), ex2->getValueWitnesses()->getAlignment());
      EXPECT_FALSE(ex2->getValueWitnesses()->isPOD());
      EXPECT_TRUE(ex2->getValueWitnesses()->isBitwiseTakable());
      EXPECT_EQ(nullptr,
                ex2->getSuperclassConstraint());
      return ex2;
    });

  ProtocolDescriptorRef protoList3[] = {
    ProtocolDescriptorRef::forSwift(&OpaqueProto1),
    ProtocolDescriptorRef::forSwift(&OpaqueProto2),
    ProtocolDescriptorRef::forSwift(&ClassProto1)
  };
  RaceTest_ExpectEqual<const ExistentialTypeMetadata *>(
    [&]() -> const ExistentialTypeMetadata * {
      auto ex3 = swift_getExistentialTypeMetadata(ProtocolClassConstraint::Class,
                                                  /*superclass=*/nullptr,
                                                  3, protoList3);
      EXPECT_EQ(MetadataKind::Existential, ex3->getKind());
      EXPECT_EQ(4 * sizeof(void*), ex3->getValueWitnesses()->getSize());
      EXPECT_EQ(alignof(void*), ex3->getValueWitnesses()->getAlignment());
      EXPECT_FALSE(ex3->getValueWitnesses()->isPOD());
      EXPECT_TRUE(ex3->getValueWitnesses()->isBitwiseTakable());
      EXPECT_EQ(nullptr,
                ex3->getSuperclassConstraint());
      return ex3;
    });
}

TEST(MetadataTest, getExistentialTypeMetadata_subclass) {
  RaceTest_ExpectEqual<const ExistentialTypeMetadata *>(
    [&]() -> const ExistentialTypeMetadata * {
      ProtocolDescriptorRef protoList1[] = {
        ProtocolDescriptorRef::forSwift(&OpaqueProto1)
      };
      auto ex1 = swift_getExistentialTypeMetadata(ProtocolClassConstraint::Class,
                                                  /*superclass=*/&MetadataTest2,
                                                  1, protoList1);
      EXPECT_EQ(MetadataKind::Existential, ex1->getKind());
      EXPECT_EQ(2 * sizeof(void*), ex1->getValueWitnesses()->getSize());
      EXPECT_EQ(alignof(void*), ex1->getValueWitnesses()->getAlignment());
      EXPECT_FALSE(ex1->getValueWitnesses()->isPOD());
      EXPECT_TRUE(ex1->getValueWitnesses()->isBitwiseTakable());
      EXPECT_EQ(ProtocolClassConstraint::Class,
                ex1->Flags.getClassConstraint());
      EXPECT_EQ(1U, ex1->NumProtocols);
      EXPECT_EQ(&OpaqueProto1, ex1->getProtocols()[0].getSwiftProtocol());
      EXPECT_EQ(&MetadataTest2, ex1->getSuperclassConstraint());
      return ex1;
    });


  RaceTest_ExpectEqual<const ExistentialTypeMetadata *>(
    [&]() -> const ExistentialTypeMetadata * {
      ProtocolDescriptorRef protoList2[] = {
        ProtocolDescriptorRef::forSwift(&OpaqueProto1),
        ProtocolDescriptorRef::forSwift(&ClassProto1)
      };
      auto ex2 = swift_getExistentialTypeMetadata(ProtocolClassConstraint::Class,
                                                  /*superclass=*/&MetadataTest2,
                                                  2, protoList2);
      EXPECT_EQ(MetadataKind::Existential, ex2->getKind());
      EXPECT_EQ(3 * sizeof(void*), ex2->getValueWitnesses()->getSize());
      EXPECT_EQ(alignof(void*), ex2->getValueWitnesses()->getAlignment());
      EXPECT_FALSE(ex2->getValueWitnesses()->isPOD());
      EXPECT_TRUE(ex2->getValueWitnesses()->isBitwiseTakable());
      EXPECT_EQ(ProtocolClassConstraint::Class,
                ex2->Flags.getClassConstraint());
      EXPECT_EQ(2U, ex2->NumProtocols);
      EXPECT_TRUE(ex2->getProtocols()[0].getSwiftProtocol() == &OpaqueProto1 &&
                  ex2->getProtocols()[1].getSwiftProtocol() == &ClassProto1);
      EXPECT_EQ(&MetadataTest2, ex2->getSuperclassConstraint());
      return ex2;
    });
}

namespace swift {
  void installCommonValueWitnesses(const TypeLayout &layout,
                                   ValueWitnessTable *vwtable);
} // namespace swift

// We cannot construct RelativeDirectPointer instances, so define
// a "shadow" struct for that purpose
struct GenericWitnessTableStorage {
  uint16_t WitnessTableSizeInWords;
  uint16_t WitnessTablePrivateSizeInWords;
  int32_t Protocol;
  int32_t Pattern;
  int32_t ResilientWitnesses;
  int32_t Instantiator;
  int32_t PrivateData;
};

template<typename T>
static void initializeRelativePointer(int32_t *ptr, T value) {
  *ptr = (int32_t)(value == nullptr ? 0 : (uintptr_t) value - (uintptr_t) ptr);
}

// Tests for resilient witness table instantiation, with runtime-provided
// default requirements

static void witnessTableInstantiator(WitnessTable *instantiatedTable,
                                     const Metadata *type,
                                     void **const *instantiationArgs) {
  EXPECT_EQ(type, nullptr);

  EXPECT_EQ(((void **) instantiatedTable)[2], (void*) 123);
  EXPECT_EQ(((void **) instantiatedTable)[3], (void*) 234);

  // The last witness is computed dynamically at instantiation time.
  ((void **) instantiatedTable)[4] = (void *) 345;

  auto conditionalTables =
      reinterpret_cast<const WitnessTable *const *>(instantiationArgs);

  EXPECT_EQ(conditionalTables[0], (void *)678);
  ((void **)instantiatedTable)[-1] = (void *)conditionalTables[0];
}

static void fakeDefaultWitness1() {}
static void fakeDefaultWitness2() {}

static void fakeRequirement1() {}
static void fakeRequirement2() {}
static void fakeRequirement3() {}
static void fakeRequirement4() {}
static void fakeRequirement5() {}

// A mock protocol descriptor with some default witnesses at the end.
//
// Note: It is not standards-compliant to compare function pointers for
// equality, so we just use fake addresses instead.
struct TestProtocol {
  ProtocolDescriptor descriptor;
  union {
    ProtocolRequirement requirements[6];
  };

  TestProtocol()
    : descriptor("TestProtocol",
                 nullptr,
                 ProtocolDescriptorFlags().withResilient(true)) {
    descriptor.NumRequirements = 6;
    initializeRelativePointer(
      (int32_t *) &descriptor.Requirements,
      requirements);

    using Flags = ProtocolRequirementFlags;

    requirements[0].Flags = Flags(Flags::Kind::BaseProtocol);
    requirements[1].Flags = Flags(Flags::Kind::Method);
    initializeRelativePointer(
      (int32_t *) &requirements[1].Function,
      fakeRequirement1);
    requirements[1].DefaultImplementation = nullptr;
    requirements[2].Flags = Flags(Flags::Kind::Method);
    initializeRelativePointer(
      (int32_t *) &requirements[2].Function,
      fakeRequirement2);
    requirements[2].DefaultImplementation = nullptr;
    requirements[3].Flags = Flags(Flags::Kind::Method);
    initializeRelativePointer(
      (int32_t *) &requirements[3].Function,
      fakeRequirement3);
    requirements[3].DefaultImplementation = nullptr;
    requirements[4].Flags = Flags(Flags::Kind::Method);
    initializeRelativePointer(
      (int32_t *) &requirements[4].Function,
      fakeRequirement4);
    initializeRelativePointer(
      (int32_t *) &requirements[4].DefaultImplementation,
      fakeDefaultWitness1);
    requirements[5].Flags = Flags(Flags::Kind::Method);
    initializeRelativePointer(
      (int32_t *) &requirements[5].Function,
      fakeRequirement5);
    initializeRelativePointer(
      (int32_t *) &requirements[5].DefaultImplementation,
      fakeDefaultWitness2);
  }
};

// All of these have to be global to relative reference each other, and
// the instantiator function.
static TestProtocol testProtocol;
static GenericWitnessTableStorage tableStorage1;
static GenericWitnessTableStorage tableStorage2;
static GenericWitnessTable::PrivateDataType tablePrivateData1;
GenericWitnessTable::PrivateDataType tablePrivateData2;

const void *witnesses[] = {
  (void *) 0,   // protocol descriptor
  (void *) 777, // base protocol reference
  (void *) 123,
  (void *) 234,
  (void *) 0,   // filled in by instantiator function
  (void *) 456,
  (void *) 567
};

WitnessTable *conditionalTablesBuffer[] = {(WitnessTable *)678};

static GenericWitnessTableStorage tableStorage3;
static GenericWitnessTable::PrivateDataType tablePrivateData3;

static void *gotFakeRequirement1[] = { (void *) fakeRequirement1 };
static void *gotFakeRequirement2[] = { (void *) fakeRequirement2 };
static void *gotFakeRequirement3[] = { (void *) fakeRequirement3 };
static void *gotFakeRequirement5[] = { (void *) fakeRequirement5 };

static void fakeWitness1() {}
static void fakeWitness2() {}
static void fakeWitness3() {}
static void fakeWitness5() {}

struct ResilientWitnessStorage {
  int32_t Requirement;
  int32_t Witness;
};

struct ResilientWitnessTableStorage {
  int32_t numWitnesses;
  ResilientWitnessStorage witnesses[4];

  ResilientWitnessTableStorage() {
    // Note the funny order -- we want to make sure it's order-independent.
    numWitnesses = 4;

    initializeRelativePointer(
      &witnesses[0].Requirement,
      &gotFakeRequirement3);
    initializeRelativePointer(
      &witnesses[0].Witness,
      fakeWitness3);

    initializeRelativePointer(
      &witnesses[1].Requirement,
      &gotFakeRequirement2);
    initializeRelativePointer(
      &witnesses[1].Witness,
      fakeWitness2);

    initializeRelativePointer(
      &witnesses[2].Requirement,
      &gotFakeRequirement1);
    initializeRelativePointer(
      &witnesses[2].Witness,
      fakeWitness1);

    initializeRelativePointer(
      &witnesses[3].Requirement,
      &gotFakeRequirement5);
    initializeRelativePointer(
      &witnesses[3].Witness,
      fakeWitness5);
  }
};

static void initialize_pod_witness_table(ValueWitnessTable &testTable) {
  testTable.size = sizeof(ValueBuffer);
  testTable.flags = ValueWitnessFlags()
    .withAlignment(alignof(ValueBuffer))
    .withPOD(true)
    .withBitwiseTakable(true)
    .withInlineStorage(true);
  testTable.stride = sizeof(ValueBuffer);
  installCommonValueWitnesses(*testTable.getTypeLayout(), &testTable);
}

TEST(TestOpaqueExistentialBox, test_assignWithCopy_pod) {
  auto any =
      swift_getExistentialTypeMetadata(ProtocolClassConstraint::Any,
                                       /*superclass=*/nullptr, 0, nullptr);
  auto anyVWT = any->getValueWitnesses();

  ValueWitnessTable testTable;
  initialize_pod_witness_table(testTable);
  FullOpaqueMetadata testMetadata = {{&testTable}, {{MetadataKind::Opaque}}};
  Metadata *metadata = &testMetadata.base;

  ValueWitnessTable testTable2;
  initialize_pod_witness_table(testTable2);
  FullOpaqueMetadata testMetadata2 = {{&testTable2}, {{MetadataKind::Opaque}}};
  Metadata *metadata2 = &testMetadata2.base;

  void *zeroPtr = nullptr;
  void *otherPtr = &zeroPtr;
  struct {
    ValueBuffer buffer;
    Metadata *type;
    uintptr_t canary;
  } existBox{{{zeroPtr, zeroPtr, zeroPtr}}, metadata, 0x5A5A5A5AU},
    existBox2{{{otherPtr, otherPtr, zeroPtr}}, metadata2, 0xB5A5A5A5U};

  anyVWT->assignWithCopy(reinterpret_cast<OpaqueValue *>(&existBox),
                         reinterpret_cast<OpaqueValue *>(&existBox2), any);
  EXPECT_EQ(existBox.type, metadata2);
  EXPECT_EQ(existBox.canary, 0x5A5A5A5AU);
  EXPECT_EQ(existBox.buffer.PrivateData[0], otherPtr);
  EXPECT_EQ(existBox.buffer.PrivateData[1], otherPtr);
  EXPECT_EQ(existBox.buffer.PrivateData[2], zeroPtr);
}

TEST(TestOpaqueExistentialBox, test_assignWithTake_pod) {
  auto any =
      swift_getExistentialTypeMetadata(ProtocolClassConstraint::Any,
                                       /*superclass=*/nullptr, 0, nullptr);
  auto anyVWT = any->getValueWitnesses();

  ValueWitnessTable testTable;
  initialize_pod_witness_table(testTable);
  FullOpaqueMetadata testMetadata = {{&testTable}, {{MetadataKind::Opaque}}};
  Metadata *metadata = &testMetadata.base;

  ValueWitnessTable testTable2;
  initialize_pod_witness_table(testTable2);
  FullOpaqueMetadata testMetadata2 = {{&testTable2}, {{MetadataKind::Opaque}}};
  Metadata *metadata2 = &testMetadata2.base;

  void *zeroPtr = nullptr;
  void *otherPtr = &zeroPtr;
  struct {
    ValueBuffer buffer;
    Metadata *type;
    uintptr_t canary;
  } existBox{{{zeroPtr, zeroPtr, zeroPtr}}, metadata, 0x5A5A5A5AU},
    existBox2{{{otherPtr, otherPtr, zeroPtr}}, metadata2, 0xB5A5A5A5U};

  anyVWT->assignWithTake(reinterpret_cast<OpaqueValue *>(&existBox),
                         reinterpret_cast<OpaqueValue *>(&existBox2), any);
  EXPECT_EQ(existBox.type, metadata2);
  EXPECT_EQ(existBox.canary, 0x5A5A5A5AU);
  EXPECT_EQ(existBox.buffer.PrivateData[0], otherPtr);
  EXPECT_EQ(existBox.buffer.PrivateData[1], otherPtr);
  EXPECT_EQ(existBox.buffer.PrivateData[2], zeroPtr);
}

static void initialize_indirect_witness_table(ValueWitnessTable &testTable) {
  testTable.size = sizeof(ValueBuffer) + 1;
  testTable.flags = ValueWitnessFlags()
    .withAlignment(alignof(ValueBuffer))
    .withPOD(true)
    .withBitwiseTakable(true)
    .withInlineStorage(false);
  testTable.stride = sizeof(ValueBuffer) + 1;
  installCommonValueWitnesses(*testTable.getTypeLayout(), &testTable);
}

TEST(TestOpaqueExistentialBox, test_assignWithCopy_indirect_indirect) {
  auto any =
      swift_getExistentialTypeMetadata(ProtocolClassConstraint::Any,
                                       /*superclass=*/nullptr, 0, nullptr);
  auto anyVWT = any->getValueWitnesses();

  ValueWitnessTable testTable;
  initialize_indirect_witness_table(testTable);
  FullOpaqueMetadata testMetadata = {{&testTable}, {{MetadataKind::Opaque}}};
  Metadata *metadata = &testMetadata.base;

  ValueWitnessTable testTable2;
  initialize_indirect_witness_table(testTable2);
  FullOpaqueMetadata testMetadata2 = {{&testTable2}, {{MetadataKind::Opaque}}};
  Metadata *metadata2 = &testMetadata2.base;

  auto refAndObjectAddr = BoxPair(swift_allocBox(metadata));
  swift_retain(refAndObjectAddr.object);
  auto refAndObjectAddr2 = BoxPair(swift_allocBox(metadata2));
  struct {
    ValueBuffer buffer;
    Metadata *type;
    uintptr_t canary;
  } existBox{{{refAndObjectAddr.object, nullptr, nullptr}}, metadata, 0x5A5A5A5AU},
    existBox2{{{refAndObjectAddr2.object, nullptr, nullptr}}, metadata2, 0xB5A5A5A5U};

  anyVWT->assignWithCopy(reinterpret_cast<OpaqueValue *>(&existBox),
                         reinterpret_cast<OpaqueValue *>(&existBox2), any);

  EXPECT_EQ(existBox.type, metadata2);
  EXPECT_EQ(existBox.canary, 0x5A5A5A5AU);
  EXPECT_EQ(existBox.buffer.PrivateData[0], refAndObjectAddr2.object);
  EXPECT_EQ(swift_retainCount(refAndObjectAddr.object), 1u);
  EXPECT_EQ(swift_retainCount(refAndObjectAddr2.object), 2u);
}

TEST(TestOpaqueExistentialBox, test_assignWithTake_indirect_indirect) {
  auto any =
      swift_getExistentialTypeMetadata(ProtocolClassConstraint::Any,
                                       /*superclass=*/nullptr, 0, nullptr);
  auto anyVWT = any->getValueWitnesses();

  ValueWitnessTable testTable;
  initialize_indirect_witness_table(testTable);
  FullOpaqueMetadata testMetadata = {{&testTable}, {{MetadataKind::Opaque}}};
  Metadata *metadata = &testMetadata.base;

  ValueWitnessTable testTable2;
  initialize_indirect_witness_table(testTable2);
  FullOpaqueMetadata testMetadata2 = {{&testTable2}, {{MetadataKind::Opaque}}};
  Metadata *metadata2 = &testMetadata2.base;

  auto refAndObjectAddr = BoxPair(swift_allocBox(metadata));
  swift_retain(refAndObjectAddr.object);
  auto refAndObjectAddr2 = BoxPair(swift_allocBox(metadata2));
  struct {
    ValueBuffer buffer;
    Metadata *type;
    uintptr_t canary;
  } existBox{{{refAndObjectAddr.object, nullptr, nullptr}}, metadata, 0x5A5A5A5AU},
    existBox2{{{refAndObjectAddr2.object, nullptr, nullptr}}, metadata2, 0xB5A5A5A5U};

  anyVWT->assignWithTake(reinterpret_cast<OpaqueValue *>(&existBox),
                         reinterpret_cast<OpaqueValue *>(&existBox2), any);

  EXPECT_EQ(existBox.type, metadata2);
  EXPECT_EQ(existBox.canary, 0x5A5A5A5AU);
  EXPECT_EQ(existBox.buffer.PrivateData[0], refAndObjectAddr2.object);
  EXPECT_EQ(swift_retainCount(refAndObjectAddr.object), 1u);
  EXPECT_EQ(swift_retainCount(refAndObjectAddr2.object), 1u);
}

TEST(TestOpaqueExistentialBox, test_assignWithCopy_pod_indirect) {
  auto any =
      swift_getExistentialTypeMetadata(ProtocolClassConstraint::Any,
                                       /*superclass=*/nullptr, 0, nullptr);
  auto anyVWT = any->getValueWitnesses();

  ValueWitnessTable testTable;
  initialize_pod_witness_table(testTable);
  FullOpaqueMetadata testMetadata = {{&testTable}, {{MetadataKind::Opaque}}};
  Metadata *metadata = &testMetadata.base;

  ValueWitnessTable testTable2;
  initialize_indirect_witness_table(testTable2);
  FullOpaqueMetadata testMetadata2 = {{&testTable2}, {{MetadataKind::Opaque}}};
  Metadata *metadata2 = &testMetadata2.base;

  auto refAndObjectAddr2 = BoxPair(swift_allocBox(metadata2));
  struct {
    ValueBuffer buffer;
    Metadata *type;
    uintptr_t canary;
  } existBox{{{nullptr, nullptr, nullptr}}, metadata, 0x5A5A5A5AU},
    existBox2{{{refAndObjectAddr2.object, nullptr, nullptr}}, metadata2, 0xB5A5A5A5U};

  anyVWT->assignWithCopy(reinterpret_cast<OpaqueValue *>(&existBox),
                         reinterpret_cast<OpaqueValue *>(&existBox2), any);

  EXPECT_EQ(existBox.type, metadata2);
  EXPECT_EQ(existBox.canary, 0x5A5A5A5AU);
  EXPECT_EQ(existBox.buffer.PrivateData[0], refAndObjectAddr2.object);
  EXPECT_EQ(swift_retainCount(refAndObjectAddr2.object), 2u);
}

TEST(TestOpaqueExistentialBox, test_assignWithTake_pod_indirect) {
  auto any =
      swift_getExistentialTypeMetadata(ProtocolClassConstraint::Any,
                                       /*superclass=*/nullptr, 0, nullptr);
  auto anyVWT = any->getValueWitnesses();

  ValueWitnessTable testTable;
  initialize_pod_witness_table(testTable);
  FullOpaqueMetadata testMetadata = {{&testTable}, {{MetadataKind::Opaque}}};
  Metadata *metadata = &testMetadata.base;

  ValueWitnessTable testTable2;
  initialize_indirect_witness_table(testTable2);
  FullOpaqueMetadata testMetadata2 = {{&testTable2}, {{MetadataKind::Opaque}}};
  Metadata *metadata2 = &testMetadata2.base;

  auto refAndObjectAddr2 = BoxPair(swift_allocBox(metadata2));
  struct {
    ValueBuffer buffer;
    Metadata *type;
    uintptr_t canary;
  } existBox{{{nullptr, nullptr, nullptr}}, metadata, 0x5A5A5A5AU},
    existBox2{{{refAndObjectAddr2.object, nullptr, nullptr}}, metadata2, 0xB5A5A5A5U};

  anyVWT->assignWithTake(reinterpret_cast<OpaqueValue *>(&existBox),
                         reinterpret_cast<OpaqueValue *>(&existBox2), any);

  EXPECT_EQ(existBox.type, metadata2);
  EXPECT_EQ(existBox.canary, 0x5A5A5A5AU);
  EXPECT_EQ(existBox.buffer.PrivateData[0], refAndObjectAddr2.object);
  EXPECT_EQ(swift_retainCount(refAndObjectAddr2.object), 1u);
}

TEST(TestOpaqueExistentialBox, test_assignWithCopy_indirect_pod) {
  auto any =
      swift_getExistentialTypeMetadata(ProtocolClassConstraint::Any,
                                       /*superclass=*/nullptr, 0, nullptr);
  auto anyVWT = any->getValueWitnesses();

  ValueWitnessTable testTable;
  initialize_pod_witness_table(testTable);
  FullOpaqueMetadata testMetadata = {{&testTable}, {{MetadataKind::Opaque}}};
  Metadata *metadata = &testMetadata.base;

  ValueWitnessTable testTable2;
  initialize_indirect_witness_table(testTable2);
  FullOpaqueMetadata testMetadata2 = {{&testTable2}, {{MetadataKind::Opaque}}};
  Metadata *metadata2 = &testMetadata2.base;

  auto refAndObjectAddr2 = BoxPair(swift_allocBox(metadata2));
  void *someAddr = &anyVWT;
  swift_retain(refAndObjectAddr2.object);
  struct {
    ValueBuffer buffer;
    Metadata *type;
    uintptr_t canary;
  } existBox2{{{someAddr, nullptr, someAddr}}, metadata, 0x5A5A5A5AU},
    existBox{{{refAndObjectAddr2.object, nullptr, nullptr}}, metadata2, 0xB5A5A5A5U};

  anyVWT->assignWithCopy(reinterpret_cast<OpaqueValue *>(&existBox),
                         reinterpret_cast<OpaqueValue *>(&existBox2), any);

  EXPECT_EQ(existBox.type, metadata);
  EXPECT_EQ(existBox.canary, 0xB5A5A5A5U);
  EXPECT_EQ(existBox.buffer.PrivateData[0], someAddr);
  EXPECT_EQ(existBox.buffer.PrivateData[1], nullptr);
  EXPECT_EQ(existBox.buffer.PrivateData[2], someAddr);
  EXPECT_EQ(swift_retainCount(refAndObjectAddr2.object), 1u);
}

TEST(TestOpaqueExistentialBox, test_assignWithTake_indirect_pod) {
  auto any =
      swift_getExistentialTypeMetadata(ProtocolClassConstraint::Any,
                                       /*superclass=*/nullptr, 0, nullptr);
  auto anyVWT = any->getValueWitnesses();

  ValueWitnessTable testTable;
  initialize_pod_witness_table(testTable);
  FullOpaqueMetadata testMetadata = {{&testTable}, {{MetadataKind::Opaque}}};
  Metadata *metadata = &testMetadata.base;

  ValueWitnessTable testTable2;
  initialize_indirect_witness_table(testTable2);
  FullOpaqueMetadata testMetadata2 = {{&testTable2}, {{MetadataKind::Opaque}}};
  Metadata *metadata2 = &testMetadata2.base;

  auto refAndObjectAddr2 = BoxPair(swift_allocBox(metadata2));
  void *someAddr = &anyVWT;
  swift_retain(refAndObjectAddr2.object);
  struct {
    ValueBuffer buffer;
    Metadata *type;
    uintptr_t canary;
  } existBox2{{{someAddr, nullptr, someAddr}}, metadata, 0x5A5A5A5AU},
    existBox{{{refAndObjectAddr2.object, nullptr, nullptr}}, metadata2, 0xB5A5A5A5U};

  anyVWT->assignWithTake(reinterpret_cast<OpaqueValue *>(&existBox),
                         reinterpret_cast<OpaqueValue *>(&existBox2), any);

  EXPECT_EQ(existBox.type, metadata);
  EXPECT_EQ(existBox.canary, 0xB5A5A5A5U);
  EXPECT_EQ(existBox.buffer.PrivateData[0], someAddr);
  EXPECT_EQ(existBox.buffer.PrivateData[1], nullptr);
  EXPECT_EQ(existBox.buffer.PrivateData[2], someAddr);
  EXPECT_EQ(swift_retainCount(refAndObjectAddr2.object), 1u);
}

TEST(TestOpaqueExistentialBox, test_initWithCopy_pod) {
  auto any =
      swift_getExistentialTypeMetadata(ProtocolClassConstraint::Any,
                                       /*superclass=*/nullptr, 0, nullptr);
  auto anyVWT = any->getValueWitnesses();

  ValueWitnessTable testTable;
  initialize_pod_witness_table(testTable);
  FullOpaqueMetadata testMetadata = {{&testTable}, {{MetadataKind::Opaque}}};
  Metadata *metadata = &testMetadata.base;

  ValueWitnessTable testTable2;
  initialize_pod_witness_table(testTable2);
  FullOpaqueMetadata testMetadata2 = {{&testTable2}, {{MetadataKind::Opaque}}};
  Metadata *metadata2 = &testMetadata2.base;

  void *zeroPtr = nullptr;
  void *otherPtr = &zeroPtr;
  struct {
    ValueBuffer buffer;
    Metadata *type;
    uintptr_t canary;
  } existBox{{{zeroPtr, zeroPtr, zeroPtr}}, metadata, 0x5A5A5A5AU},
    existBox2{{{otherPtr, otherPtr, zeroPtr}}, metadata2, 0xB5A5A5A5U};

  anyVWT->initializeWithCopy(reinterpret_cast<OpaqueValue *>(&existBox),
                       reinterpret_cast<OpaqueValue *>(&existBox2), any);
  EXPECT_EQ(existBox.type, metadata2);
  EXPECT_EQ(existBox.canary, 0x5A5A5A5AU);
  EXPECT_EQ(existBox.buffer.PrivateData[0], otherPtr);
  EXPECT_EQ(existBox.buffer.PrivateData[1], otherPtr);
  EXPECT_EQ(existBox.buffer.PrivateData[2], zeroPtr);
}

TEST(TestOpaqueExistentialBox, test_initWithTake_pod) {
  auto any =
      swift_getExistentialTypeMetadata(ProtocolClassConstraint::Any,
                                       /*superclass=*/nullptr, 0, nullptr);
  auto anyVWT = any->getValueWitnesses();

  ValueWitnessTable testTable;
  initialize_pod_witness_table(testTable);
  FullOpaqueMetadata testMetadata = {{&testTable}, {{MetadataKind::Opaque}}};
  Metadata *metadata = &testMetadata.base;

  ValueWitnessTable testTable2;
  initialize_pod_witness_table(testTable2);
  FullOpaqueMetadata testMetadata2 = {{&testTable2}, {{MetadataKind::Opaque}}};
  Metadata *metadata2 = &testMetadata2.base;

  void *zeroPtr = nullptr;
  void *otherPtr = &zeroPtr;
  struct {
    ValueBuffer buffer;
    Metadata *type;
    uintptr_t canary;
  } existBox{{{zeroPtr, zeroPtr, zeroPtr}}, metadata, 0x5A5A5A5AU},
    existBox2{{{otherPtr, otherPtr, zeroPtr}}, metadata2, 0xB5A5A5A5U};

  anyVWT->initializeWithTake(reinterpret_cast<OpaqueValue *>(&existBox),
                       reinterpret_cast<OpaqueValue *>(&existBox2), any);
  EXPECT_EQ(existBox.type, metadata2);
  EXPECT_EQ(existBox.canary, 0x5A5A5A5AU);
  EXPECT_EQ(existBox.buffer.PrivateData[0], otherPtr);
  EXPECT_EQ(existBox.buffer.PrivateData[1], otherPtr);
  EXPECT_EQ(existBox.buffer.PrivateData[2], zeroPtr);
}

TEST(TestOpaqueExistentialBox, test_initWithCopy_indirect) {
  auto any =
      swift_getExistentialTypeMetadata(ProtocolClassConstraint::Any,
                                       /*superclass=*/nullptr, 0, nullptr);
  auto anyVWT = any->getValueWitnesses();

  ValueWitnessTable testTable;
  initialize_pod_witness_table(testTable);
  FullOpaqueMetadata testMetadata = {{&testTable}, {{MetadataKind::Opaque}}};
  Metadata *metadata = &testMetadata.base;

  ValueWitnessTable testTable2;
  initialize_indirect_witness_table(testTable2);
  FullOpaqueMetadata testMetadata2 = {{&testTable2}, {{MetadataKind::Opaque}}};
  Metadata *metadata2 = &testMetadata2.base;

  auto refAndObjectAddr2 = BoxPair(swift_allocBox(metadata2));
  struct {
    ValueBuffer buffer;
    Metadata *type;
    uintptr_t canary;
  } existBox{{{nullptr, nullptr, nullptr}}, metadata, 0x5A5A5A5AU},
    existBox2{{{refAndObjectAddr2.object, nullptr, nullptr}}, metadata2, 0xB5A5A5A5U};

  anyVWT->initializeWithCopy(reinterpret_cast<OpaqueValue *>(&existBox),
                             reinterpret_cast<OpaqueValue *>(&existBox2), any);

  EXPECT_EQ(existBox.type, metadata2);
  EXPECT_EQ(existBox.canary, 0x5A5A5A5AU);
  EXPECT_EQ(existBox.buffer.PrivateData[0], refAndObjectAddr2.object);
  EXPECT_EQ(swift_retainCount(refAndObjectAddr2.object), 2u);
}

TEST(TestOpaqueExistentialBox, test_initWithTake_indirect) {
  auto any =
      swift_getExistentialTypeMetadata(ProtocolClassConstraint::Any,
                                       /*superclass=*/nullptr, 0, nullptr);
  auto anyVWT = any->getValueWitnesses();

  ValueWitnessTable testTable;
  initialize_pod_witness_table(testTable);
  FullOpaqueMetadata testMetadata = {{&testTable}, {{MetadataKind::Opaque}}};
  Metadata *metadata = &testMetadata.base;

  ValueWitnessTable testTable2;
  initialize_indirect_witness_table(testTable2);
  FullOpaqueMetadata testMetadata2 = {{&testTable2}, {{MetadataKind::Opaque}}};
  Metadata *metadata2 = &testMetadata2.base;

  auto refAndObjectAddr2 = BoxPair(swift_allocBox(metadata2));
  struct {
    ValueBuffer buffer;
    Metadata *type;
    uintptr_t canary;
  } existBox{{{nullptr, nullptr, nullptr}}, metadata, 0x5A5A5A5AU},
    existBox2{{{refAndObjectAddr2.object, nullptr, nullptr}}, metadata2, 0xB5A5A5A5U};

  anyVWT->initializeWithTake(reinterpret_cast<OpaqueValue *>(&existBox),
                             reinterpret_cast<OpaqueValue *>(&existBox2), any);

  EXPECT_EQ(existBox.type, metadata2);
  EXPECT_EQ(existBox.canary, 0x5A5A5A5AU);
  EXPECT_EQ(existBox.buffer.PrivateData[0], refAndObjectAddr2.object);
  EXPECT_EQ(swift_retainCount(refAndObjectAddr2.object), 1u);
}
#endif