//===- EntityLinkerTest.cpp -----------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

#include "clang/ScalableStaticAnalysisFramework/Core/EntityLinker/EntityLinker.h"
#include "TestFixture.h"
#include "clang/ScalableStaticAnalysisFramework/Core/EntityLinker/EntitySummaryEncoding.h"
#include "clang/ScalableStaticAnalysisFramework/Core/EntityLinker/LUSummaryEncoding.h"
#include "clang/ScalableStaticAnalysisFramework/Core/EntityLinker/TUSummaryEncoding.h"
#include "clang/ScalableStaticAnalysisFramework/Core/Model/BuildNamespace.h"
#include "clang/ScalableStaticAnalysisFramework/Core/Model/EntityId.h"
#include "clang/ScalableStaticAnalysisFramework/Core/Model/EntityIdTable.h"
#include "clang/ScalableStaticAnalysisFramework/Core/Model/EntityLinkage.h"
#include "clang/ScalableStaticAnalysisFramework/Core/Model/EntityName.h"
#include "clang/ScalableStaticAnalysisFramework/Core/Model/SummaryName.h"
#include "llvm/Testing/Support/Error.h"
#include "gmock/gmock.h"
#include "gtest/gtest.h"
#include <memory>

using namespace clang::ssaf;
using namespace llvm;
using ::testing::HasSubstr;
using ::testing::Not;
using ::testing::PrintToString;

namespace {

class MockEntitySummaryEncoding : public EntitySummaryEncoding {
public:
  MockEntitySummaryEncoding() : Id(++Index) {}

  size_t getId() const { return Id; }

  llvm::Error
  patch(const std::map<EntityId, EntityId> &EntityResolutionTable) override {
    PatchedIds = EntityResolutionTable;
    return llvm::Error::success();
  }

  const std::map<EntityId, EntityId> &getPatchedIds() const {
    return PatchedIds;
  }

  static size_t Index;

private:
  size_t Id;
  std::map<EntityId, EntityId> PatchedIds;
};

size_t MockEntitySummaryEncoding::Index = 0;

class EntityLinkerTest : public TestFixture {
protected:
  static constexpr EntityLinkage NoneLinkage =
      EntityLinkage(EntityLinkageType::None);
  static constexpr EntityLinkage InternalLinkage =
      EntityLinkage(EntityLinkageType::Internal);
  static constexpr EntityLinkage ExternalLinkage =
      EntityLinkage(EntityLinkageType::External);

  void SetUp() override {
    // This ensures that the MockEntitySummary id assignment does not
    // accidentally depend on test execution order.
    MockEntitySummaryEncoding::Index = 0;
  }

  std::unique_ptr<TUSummaryEncoding>
  createTUSummaryEncoding(BuildNamespaceKind Kind, llvm::StringRef Name) {
    return std::make_unique<TUSummaryEncoding>(BuildNamespace(Kind, Name));
  }

  size_t addSummaryData(TUSummaryEncoding &TU, EntityId EId,
                        llvm::StringRef SummaryNameStr) {
    SummaryName SN(SummaryNameStr.str());
    auto Summary = std::make_unique<MockEntitySummaryEncoding>();
    const size_t ESId = Summary->getId();
    getData(TU)[SN][EId] = std::move(Summary);
    return ESId;
  }

  EntityId addEntity(TUSummaryEncoding &TU, llvm::StringRef USR,
                     EntityLinkage Linkage) {
    EntityName Name(USR, "", NestedBuildNamespace());
    EntityId Id = getIdTable(TU).getId(Name);
    getLinkageTable(TU).insert({Id, Linkage});
    return Id;
  }
};

// ============================================================================
// Entity ID Table Matchers
// ============================================================================

MATCHER_P(ContainsEntity, EntityName,
          std::string(negation ? "does not contain" : "contains") +
              " entity '" + PrintToString(EntityName) + "'") {
  return arg.contains(EntityName);
}

MATCHER_P(IdTableHasSize, ExpectedCount,
          std::string("has ") + PrintToString(ExpectedCount) + " entities") {
  if (arg.count() != ExpectedCount) {
    *result_listener << "has " << arg.count() << " entities";
    return false;
  }
  return true;
}

// ============================================================================
// Linkage Table Matchers
// ============================================================================

MATCHER_P2(EntityHasLinkage, EId, ExpectedLinkage,
           std::string("entity has ") + PrintToString(ExpectedLinkage) +
               " linkage") {
  auto It = arg.find(EId);
  if (It == arg.end()) {
    *result_listener << "entity " << PrintToString(EId)
                     << " not found in linkage table";
    return false;
  }

  const EntityLinkage &ActualLinkage = It->second;
  if (ActualLinkage != ExpectedLinkage) {
    *result_listener << "entity " << PrintToString(EId) << " has linkage "
                     << PrintToString(ActualLinkage);
    return false;
  }

  return true;
}

MATCHER_P(LinkageTableHasSize, ExpectedSize,
          std::string("linkage table has size ") +
              PrintToString(ExpectedSize)) {
  if (arg.size() != ExpectedSize) {
    *result_listener << "has size " << arg.size();
    return false;
  }
  return true;
}

// ============================================================================
// Summary Data Matchers
// ============================================================================

MATCHER_P3(HasSummaryData, EId, ExpectedMockId, ExpectedResolutionMapping,
           std::string("has summary data for entity with expected mock ID ") +
               PrintToString(ExpectedMockId)) {

  auto It = arg.find(EId);
  if (It == arg.end()) {
    *result_listener << "entity " << PrintToString(EId)
                     << " not found in summary data";
    return false;
  }

  auto *Mock = static_cast<const MockEntitySummaryEncoding *>(It->second.get());

  if (Mock->getId() != ExpectedMockId) {
    *result_listener << "entity " << PrintToString(EId) << " has mock ID "
                     << Mock->getId() << " (expected " << ExpectedMockId << ")";
    return false;
  }

  if (Mock->getPatchedIds() != ExpectedResolutionMapping) {
    *result_listener << "entity " << PrintToString(EId)
                     << " has different resolution mapping";
    return false;
  }

  return true;
}

MATCHER_P(SummaryDataHasSize, ExpectedSize,
          std::string("summary data has size ") + PrintToString(ExpectedSize)) {
  if (arg.size() != ExpectedSize) {
    *result_listener << "has size " << arg.size();
    return false;
  }
  return true;
}

// ============================================================================
// ENTITY LINKER TESTS
// ============================================================================

TEST_F(EntityLinkerTest, CreatesEmptyLinker) {
  NestedBuildNamespace LUNamespace(
      {BuildNamespace(BuildNamespaceKind::LinkUnit, "LU")});

  EntityLinker Linker(LUNamespace);

  const auto Output = std::move(Linker).takeOutput();
  EXPECT_EQ(getIdTable(Output).count(), 0u);
  EXPECT_EQ(getLinkageTable(Output).size(), 0u);
  EXPECT_EQ(getData(Output).size(), 0u);
}

TEST_F(EntityLinkerTest, LinksEmptyTranslationUnit) {
  NestedBuildNamespace LUNamespace(
      {BuildNamespace(BuildNamespaceKind::LinkUnit, "LU")});

  EntityLinker Linker(LUNamespace);

  auto TUEmpty =
      createTUSummaryEncoding(BuildNamespaceKind::CompilationUnit, "TUEmpty");

  EXPECT_THAT_ERROR(Linker.link(std::move(TUEmpty)), llvm::Succeeded());

  const auto Output = std::move(Linker).takeOutput();
  EXPECT_EQ(getIdTable(Output).count(), 0u);
  EXPECT_EQ(getLinkageTable(Output).size(), 0u);
  EXPECT_EQ(getData(Output).size(), 0u);
}

TEST_F(EntityLinkerTest, LinksOneTranslationUnit) {
  NestedBuildNamespace LUNamespace(
      {BuildNamespace(BuildNamespaceKind::LinkUnit, "LU")});

  EntityLinker Linker(LUNamespace);

  auto TU = createTUSummaryEncoding(BuildNamespaceKind::CompilationUnit, "TU");

  const auto TU_A_Id = addEntity(*TU, "A", NoneLinkage);
  const auto TU_A_S1_Data = addSummaryData(*TU, TU_A_Id, "S1");
  const auto TU_A_S2_Data = addSummaryData(*TU, TU_A_Id, "S2");

  const auto TU_B_Id = addEntity(*TU, "B", InternalLinkage);
  const auto TU_B_S1_Data = addSummaryData(*TU, TU_B_Id, "S1");
  const auto TU_B_S2_Data = addSummaryData(*TU, TU_B_Id, "S2");

  const auto TU_C_Id = addEntity(*TU, "C", ExternalLinkage);
  const auto TU_C_S1_Data = addSummaryData(*TU, TU_C_Id, "S1");

  const auto TU_D_Id = addEntity(*TU, "D", ExternalLinkage);
  const auto TU_D_S2_Data = addSummaryData(*TU, TU_D_Id, "S2");

  const BuildNamespace TUNamespace = getTUNamespace(*TU);

  ASSERT_THAT_ERROR(Linker.link(std::move(TU)), llvm::Succeeded());

  const auto Output = std::move(Linker).takeOutput();
  const auto &IdTable = getIdTable(Output);
  const auto &Entities = getEntities(IdTable);
  const auto &LinkageTable = getLinkageTable(Output);
  const auto &Data = getData(Output);

  NestedBuildNamespace LocalNamespace =
      NestedBuildNamespace(TUNamespace).makeQualified(LUNamespace);

  EntityName LU_A_Name("A", "", LocalNamespace);
  EntityName LU_B_Name("B", "", LocalNamespace);
  EntityName LU_C_Name("C", "", LUNamespace);
  EntityName LU_D_Name("D", "", LUNamespace);

  // EntityIdTable Tests.
  {
    ASSERT_THAT(IdTable, IdTableHasSize(4u));
    ASSERT_THAT(IdTable, ContainsEntity(LU_A_Name));
    ASSERT_THAT(IdTable, ContainsEntity(LU_B_Name));
    ASSERT_THAT(IdTable, ContainsEntity(LU_C_Name));
    ASSERT_THAT(IdTable, ContainsEntity(LU_D_Name));
  }

  // This is safe since we confirmed that these entities are present in the
  // block above.
  const auto LU_A_Id = Entities.at(LU_A_Name);
  const auto LU_B_Id = Entities.at(LU_B_Name);
  const auto LU_C_Id = Entities.at(LU_C_Name);
  const auto LU_D_Id = Entities.at(LU_D_Name);

  // LinkageTable Tests.
  {
    ASSERT_THAT(LinkageTable, LinkageTableHasSize(4u));
    ASSERT_THAT(LinkageTable, EntityHasLinkage(LU_A_Id, NoneLinkage));
    ASSERT_THAT(LinkageTable, EntityHasLinkage(LU_B_Id, InternalLinkage));
    ASSERT_THAT(LinkageTable, EntityHasLinkage(LU_C_Id, ExternalLinkage));
    ASSERT_THAT(LinkageTable, EntityHasLinkage(LU_D_Id, ExternalLinkage));
  }

  std::map<EntityId, EntityId> Resolution = {{TU_A_Id, LU_A_Id},
                                             {TU_B_Id, LU_B_Id},
                                             {TU_C_Id, LU_C_Id},
                                             {TU_D_Id, LU_D_Id}};

  // Data Tests.
  {
    ASSERT_EQ(Data.size(), 2u);

    // S1 Data Tests.
    {
      SummaryName S1("S1");
      ASSERT_NE(Data.find(S1), Data.end());
      const auto &S1Data = Data.at(S1);

      ASSERT_THAT(S1Data, SummaryDataHasSize(3u));
      ASSERT_THAT(S1Data, HasSummaryData(LU_A_Id, TU_A_S1_Data, Resolution));
      ASSERT_THAT(S1Data, HasSummaryData(LU_B_Id, TU_B_S1_Data, Resolution));
      ASSERT_THAT(S1Data, HasSummaryData(LU_C_Id, TU_C_S1_Data, Resolution));
    }

    // S2 Data Tests.
    {
      SummaryName S2("S2");
      ASSERT_NE(Data.find(S2), Data.end());
      const auto &S2Data = Data.at(S2);

      ASSERT_THAT(S2Data, SummaryDataHasSize(3u));
      ASSERT_THAT(S2Data, HasSummaryData(LU_A_Id, TU_A_S2_Data, Resolution));
      ASSERT_THAT(S2Data, HasSummaryData(LU_B_Id, TU_B_S2_Data, Resolution));
      ASSERT_THAT(S2Data, HasSummaryData(LU_D_Id, TU_D_S2_Data, Resolution));
    }
  }
}

TEST_F(EntityLinkerTest, LinksTwoTranslationUnits) {
  NestedBuildNamespace LUNamespace(
      {BuildNamespace(BuildNamespaceKind::LinkUnit, "LU")});

  EntityLinker Linker(LUNamespace);

  auto TU1 =
      createTUSummaryEncoding(BuildNamespaceKind::CompilationUnit, "TU1");

  // None linkage entities in TU1
  const auto TU1_X_Id = addEntity(*TU1, "X", NoneLinkage);
  const auto TU1_X_S1_Data = addSummaryData(*TU1, TU1_X_Id, "S1");

  const auto TU1_Y_Id = addEntity(*TU1, "Y", NoneLinkage);
  const auto TU1_Y_S2_Data = addSummaryData(*TU1, TU1_Y_Id, "S2");

  const auto TU1_Z_Id = addEntity(*TU1, "Z", NoneLinkage);
  const auto TU1_Z_S1_Data = addSummaryData(*TU1, TU1_Z_Id, "S1");
  const auto TU1_Z_S2_Data = addSummaryData(*TU1, TU1_Z_Id, "S2");

  // Internal linkage entities in TU1
  const auto TU1_A_Id = addEntity(*TU1, "A", InternalLinkage);
  const auto TU1_A_S1_Data = addSummaryData(*TU1, TU1_A_Id, "S1");

  const auto TU1_B_Id = addEntity(*TU1, "B", InternalLinkage);
  const auto TU1_B_S2_Data = addSummaryData(*TU1, TU1_B_Id, "S2");

  const auto TU1_C_Id = addEntity(*TU1, "C", InternalLinkage);
  const auto TU1_C_S1_Data = addSummaryData(*TU1, TU1_C_Id, "S1");
  const auto TU1_C_S2_Data = addSummaryData(*TU1, TU1_C_Id, "S2");

  // External linkage entities in TU1
  const auto TU1_P_Id = addEntity(*TU1, "P", ExternalLinkage);
  const auto TU1_P_S1_Data = addSummaryData(*TU1, TU1_P_Id, "S1");

  const auto TU1_Q_Id = addEntity(*TU1, "Q", ExternalLinkage);
  const auto TU1_Q_S2_Data = addSummaryData(*TU1, TU1_Q_Id, "S2");

  const auto TU1_R_Id = addEntity(*TU1, "R", ExternalLinkage);
  const auto TU1_R_S1_Data = addSummaryData(*TU1, TU1_R_Id, "S1");
  const auto TU1_R_S2_Data = addSummaryData(*TU1, TU1_R_Id, "S2");

  const BuildNamespace TU1Namespace = getTUNamespace(*TU1);

  ASSERT_THAT_ERROR(Linker.link(std::move(TU1)), llvm::Succeeded());

  auto TU2 =
      createTUSummaryEncoding(BuildNamespaceKind::CompilationUnit, "TU2");

  // None linkage entities in TU2 - includes duplicates and uniques
  const auto TU2_X_Id = addEntity(*TU2, "X", NoneLinkage);
  const auto TU2_X_S2_Data = addSummaryData(*TU2, TU2_X_Id, "S2");

  const auto TU2_Y_Id = addEntity(*TU2, "Y", NoneLinkage);
  const auto TU2_Y_S1_Data = addSummaryData(*TU2, TU2_Y_Id, "S1");

  const auto TU2_W_Id = addEntity(*TU2, "W", NoneLinkage);
  const auto TU2_W_S1_Data = addSummaryData(*TU2, TU2_W_Id, "S1");
  const auto TU2_W_S2_Data = addSummaryData(*TU2, TU2_W_Id, "S2");

  // Internal linkage entities in TU2 - includes duplicates and unique
  const auto TU2_A_Id = addEntity(*TU2, "A", InternalLinkage);
  const auto TU2_A_S2_Data = addSummaryData(*TU2, TU2_A_Id, "S2");

  const auto TU2_B_Id = addEntity(*TU2, "B", InternalLinkage);
  const auto TU2_B_S1_Data = addSummaryData(*TU2, TU2_B_Id, "S1");

  const auto TU2_D_Id = addEntity(*TU2, "D", InternalLinkage);
  const auto TU2_D_S1_Data = addSummaryData(*TU2, TU2_D_Id, "S1");
  const auto TU2_D_S2_Data = addSummaryData(*TU2, TU2_D_Id, "S2");

  // External linkage entities in TU2 - includes duplicates (will be dropped)
  // and uniques
  const auto TU2_P_Id = addEntity(*TU2, "P", ExternalLinkage);
  const auto TU2_P_S2_Data = addSummaryData(*TU2, TU2_P_Id, "S2");

  const auto TU2_Q_Id = addEntity(*TU2, "Q", ExternalLinkage);
  const auto TU2_Q_S1_Data = addSummaryData(*TU2, TU2_Q_Id, "S1");

  const auto TU2_R_Id = addEntity(*TU2, "R", ExternalLinkage);
  const auto TU2_R_S1_Data = addSummaryData(*TU2, TU2_R_Id, "S1");
  const auto TU2_R_S2_Data = addSummaryData(*TU2, TU2_R_Id, "S2");

  const auto TU2_S_Id = addEntity(*TU2, "S", ExternalLinkage);
  const auto TU2_S_S1_Data = addSummaryData(*TU2, TU2_S_Id, "S1");
  const auto TU2_S_S2_Data = addSummaryData(*TU2, TU2_S_Id, "S2");

  const BuildNamespace TU2Namespace = getTUNamespace(*TU2);

  ASSERT_THAT_ERROR(Linker.link(std::move(TU2)), llvm::Succeeded());

  const auto Output = std::move(Linker).takeOutput();
  const auto &IdTable = getIdTable(Output);
  const auto &Entities = getEntities(IdTable);
  const auto &LinkageTable = getLinkageTable(Output);
  const auto &Data = getData(Output);

  NestedBuildNamespace TU1LocalNamespace =
      NestedBuildNamespace(TU1Namespace).makeQualified(LUNamespace);

  NestedBuildNamespace TU2LocalNamespace =
      NestedBuildNamespace(TU2Namespace).makeQualified(LUNamespace);

  // None linkage entities use local namespace (TU scoped)
  EntityName LU_TU1_X_Name("X", "", TU1LocalNamespace);
  EntityName LU_TU1_Y_Name("Y", "", TU1LocalNamespace);
  EntityName LU_TU1_Z_Name("Z", "", TU1LocalNamespace);
  EntityName LU_TU2_X_Name("X", "", TU2LocalNamespace);
  EntityName LU_TU2_Y_Name("Y", "", TU2LocalNamespace);
  EntityName LU_TU2_W_Name("W", "", TU2LocalNamespace);

  // Internal linkage entities use local namespace (TU scoped)
  EntityName LU_TU1_A_Name("A", "", TU1LocalNamespace);
  EntityName LU_TU1_B_Name("B", "", TU1LocalNamespace);
  EntityName LU_TU1_C_Name("C", "", TU1LocalNamespace);
  EntityName LU_TU2_A_Name("A", "", TU2LocalNamespace);
  EntityName LU_TU2_B_Name("B", "", TU2LocalNamespace);
  EntityName LU_TU2_D_Name("D", "", TU2LocalNamespace);

  // External linkage entities use LU namespace (shared across TUs)
  EntityName LU_P_Name("P", "", LUNamespace);
  EntityName LU_Q_Name("Q", "", LUNamespace);
  EntityName LU_R_Name("R", "", LUNamespace);
  EntityName LU_S_Name("S", "", LUNamespace);

  // EntityIdTable Tests.
  {
    // Should have 6 None + 6 Internal + 4 External = 16 entities total
    ASSERT_THAT(IdTable, IdTableHasSize(16u));

    ASSERT_THAT(IdTable, ContainsEntity(LU_TU1_X_Name));
    ASSERT_THAT(IdTable, ContainsEntity(LU_TU1_Y_Name));
    ASSERT_THAT(IdTable, ContainsEntity(LU_TU1_Z_Name));
    ASSERT_THAT(IdTable, ContainsEntity(LU_TU2_X_Name));
    ASSERT_THAT(IdTable, ContainsEntity(LU_TU2_Y_Name));
    ASSERT_THAT(IdTable, ContainsEntity(LU_TU2_W_Name));

    ASSERT_THAT(IdTable, ContainsEntity(LU_TU1_A_Name));
    ASSERT_THAT(IdTable, ContainsEntity(LU_TU1_B_Name));
    ASSERT_THAT(IdTable, ContainsEntity(LU_TU1_C_Name));
    ASSERT_THAT(IdTable, ContainsEntity(LU_TU2_A_Name));
    ASSERT_THAT(IdTable, ContainsEntity(LU_TU2_B_Name));
    ASSERT_THAT(IdTable, ContainsEntity(LU_TU2_D_Name));

    ASSERT_THAT(IdTable, ContainsEntity(LU_P_Name));
    ASSERT_THAT(IdTable, ContainsEntity(LU_Q_Name));
    ASSERT_THAT(IdTable, ContainsEntity(LU_R_Name));
    ASSERT_THAT(IdTable, ContainsEntity(LU_S_Name));
  }

  // This is safe since we confirmed that these entities are present in the
  // block above.
  const auto LU_TU1_X_Id = Entities.at(LU_TU1_X_Name);
  const auto LU_TU1_Y_Id = Entities.at(LU_TU1_Y_Name);
  const auto LU_TU1_Z_Id = Entities.at(LU_TU1_Z_Name);
  const auto LU_TU2_X_Id = Entities.at(LU_TU2_X_Name);
  const auto LU_TU2_Y_Id = Entities.at(LU_TU2_Y_Name);
  const auto LU_TU2_W_Id = Entities.at(LU_TU2_W_Name);
  const auto LU_TU1_A_Id = Entities.at(LU_TU1_A_Name);
  const auto LU_TU1_B_Id = Entities.at(LU_TU1_B_Name);
  const auto LU_TU1_C_Id = Entities.at(LU_TU1_C_Name);
  const auto LU_TU2_A_Id = Entities.at(LU_TU2_A_Name);
  const auto LU_TU2_B_Id = Entities.at(LU_TU2_B_Name);
  const auto LU_TU2_D_Id = Entities.at(LU_TU2_D_Name);
  const auto LU_P_Id = Entities.at(LU_P_Name);
  const auto LU_Q_Id = Entities.at(LU_Q_Name);
  const auto LU_R_Id = Entities.at(LU_R_Name);
  const auto LU_S_Id = Entities.at(LU_S_Name);

  // LinkageTable Tests.
  {
    ASSERT_THAT(LinkageTable, LinkageTableHasSize(16u));

    ASSERT_THAT(LinkageTable, EntityHasLinkage(LU_TU1_X_Id, NoneLinkage));
    ASSERT_THAT(LinkageTable, EntityHasLinkage(LU_TU1_Y_Id, NoneLinkage));
    ASSERT_THAT(LinkageTable, EntityHasLinkage(LU_TU1_Z_Id, NoneLinkage));
    ASSERT_THAT(LinkageTable, EntityHasLinkage(LU_TU2_X_Id, NoneLinkage));
    ASSERT_THAT(LinkageTable, EntityHasLinkage(LU_TU2_Y_Id, NoneLinkage));
    ASSERT_THAT(LinkageTable, EntityHasLinkage(LU_TU2_W_Id, NoneLinkage));

    ASSERT_THAT(LinkageTable, EntityHasLinkage(LU_TU1_A_Id, InternalLinkage));
    ASSERT_THAT(LinkageTable, EntityHasLinkage(LU_TU1_B_Id, InternalLinkage));
    ASSERT_THAT(LinkageTable, EntityHasLinkage(LU_TU1_C_Id, InternalLinkage));
    ASSERT_THAT(LinkageTable, EntityHasLinkage(LU_TU2_A_Id, InternalLinkage));
    ASSERT_THAT(LinkageTable, EntityHasLinkage(LU_TU2_B_Id, InternalLinkage));
    ASSERT_THAT(LinkageTable, EntityHasLinkage(LU_TU2_D_Id, InternalLinkage));

    ASSERT_THAT(LinkageTable, EntityHasLinkage(LU_P_Id, ExternalLinkage));
    ASSERT_THAT(LinkageTable, EntityHasLinkage(LU_Q_Id, ExternalLinkage));
    ASSERT_THAT(LinkageTable, EntityHasLinkage(LU_R_Id, ExternalLinkage));
    ASSERT_THAT(LinkageTable, EntityHasLinkage(LU_S_Id, ExternalLinkage));
  }

  // Data Tests.
  {
    ASSERT_EQ(Data.size(), 2u);

    // Build entity resolution mappings for each TU.
    std::map<EntityId, EntityId> TU1Resolution = {
        {TU1_X_Id, LU_TU1_X_Id}, {TU1_Y_Id, LU_TU1_Y_Id},
        {TU1_Z_Id, LU_TU1_Z_Id}, {TU1_A_Id, LU_TU1_A_Id},
        {TU1_B_Id, LU_TU1_B_Id}, {TU1_C_Id, LU_TU1_C_Id},
        {TU1_P_Id, LU_P_Id},     {TU1_Q_Id, LU_Q_Id},
        {TU1_R_Id, LU_R_Id}};

    std::map<EntityId, EntityId> TU2Resolution = {
        {TU2_X_Id, LU_TU2_X_Id}, {TU2_Y_Id, LU_TU2_Y_Id},
        {TU2_W_Id, LU_TU2_W_Id}, {TU2_A_Id, LU_TU2_A_Id},
        {TU2_B_Id, LU_TU2_B_Id}, {TU2_D_Id, LU_TU2_D_Id},
        {TU2_P_Id, LU_P_Id},     {TU2_Q_Id, LU_Q_Id},
        {TU2_R_Id, LU_R_Id},     {TU2_S_Id, LU_S_Id}};

    // S1 Data Tests.
    {
      SummaryName S1("S1");
      ASSERT_NE(Data.find(S1), Data.end());
      const auto &S1Data = Data.at(S1);

      // S1 should contain: TU1(X,Z,A,C,P,R) + TU2(Y,W,B,D,Q,S) = 12 entities.
      ASSERT_THAT(S1Data, SummaryDataHasSize(12u));

      // TU1 entities in S1.
      ASSERT_THAT(S1Data,
                  HasSummaryData(LU_TU1_X_Id, TU1_X_S1_Data, TU1Resolution));
      ASSERT_THAT(S1Data,
                  HasSummaryData(LU_TU1_Z_Id, TU1_Z_S1_Data, TU1Resolution));
      ASSERT_THAT(S1Data,
                  HasSummaryData(LU_TU1_A_Id, TU1_A_S1_Data, TU1Resolution));
      ASSERT_THAT(S1Data,
                  HasSummaryData(LU_TU1_C_Id, TU1_C_S1_Data, TU1Resolution));
      ASSERT_THAT(S1Data,
                  HasSummaryData(LU_P_Id, TU1_P_S1_Data, TU1Resolution));
      ASSERT_THAT(S1Data,
                  HasSummaryData(LU_R_Id, TU1_R_S1_Data, TU1Resolution));

      // TU2 entities in S1.
      ASSERT_THAT(S1Data,
                  HasSummaryData(LU_TU2_Y_Id, TU2_Y_S1_Data, TU2Resolution));
      ASSERT_THAT(S1Data,
                  HasSummaryData(LU_TU2_W_Id, TU2_W_S1_Data, TU2Resolution));
      ASSERT_THAT(S1Data,
                  HasSummaryData(LU_TU2_B_Id, TU2_B_S1_Data, TU2Resolution));
      ASSERT_THAT(S1Data,
                  HasSummaryData(LU_TU2_D_Id, TU2_D_S1_Data, TU2Resolution));
      ASSERT_THAT(S1Data,
                  HasSummaryData(LU_Q_Id, TU2_Q_S1_Data, TU2Resolution));
      ASSERT_THAT(S1Data,
                  Not(HasSummaryData(LU_R_Id, TU2_R_S1_Data, TU2Resolution)));
      ASSERT_THAT(S1Data,
                  HasSummaryData(LU_S_Id, TU2_S_S1_Data, TU2Resolution));
    }

    // S2 Data Tests.
    {
      SummaryName S2("S2");
      ASSERT_NE(Data.find(S2), Data.end());
      const auto &S2Data = Data.at(S2);

      // S2 should contain: TU1(Y,Z,B,C,Q,R) + TU2(X,W,A,D,P,S) = 12 entities.
      ASSERT_THAT(S2Data, SummaryDataHasSize(12u));

      // TU1 entities in S2.
      ASSERT_THAT(S2Data,
                  HasSummaryData(LU_TU1_Y_Id, TU1_Y_S2_Data, TU1Resolution));
      ASSERT_THAT(S2Data,
                  HasSummaryData(LU_TU1_Z_Id, TU1_Z_S2_Data, TU1Resolution));
      ASSERT_THAT(S2Data,
                  HasSummaryData(LU_TU1_B_Id, TU1_B_S2_Data, TU1Resolution));
      ASSERT_THAT(S2Data,
                  HasSummaryData(LU_TU1_C_Id, TU1_C_S2_Data, TU1Resolution));
      ASSERT_THAT(S2Data,
                  HasSummaryData(LU_Q_Id, TU1_Q_S2_Data, TU1Resolution));
      ASSERT_THAT(S2Data,
                  HasSummaryData(LU_R_Id, TU1_R_S2_Data, TU1Resolution));

      // TU2 entities in S2.
      ASSERT_THAT(S2Data,
                  HasSummaryData(LU_TU2_X_Id, TU2_X_S2_Data, TU2Resolution));
      ASSERT_THAT(S2Data,
                  HasSummaryData(LU_TU2_W_Id, TU2_W_S2_Data, TU2Resolution));
      ASSERT_THAT(S2Data,
                  HasSummaryData(LU_TU2_A_Id, TU2_A_S2_Data, TU2Resolution));
      ASSERT_THAT(S2Data,
                  HasSummaryData(LU_TU2_D_Id, TU2_D_S2_Data, TU2Resolution));
      ASSERT_THAT(S2Data,
                  HasSummaryData(LU_P_Id, TU2_P_S2_Data, TU2Resolution));
      ASSERT_THAT(S2Data,
                  Not(HasSummaryData(LU_R_Id, TU2_R_S2_Data, TU2Resolution)));
      ASSERT_THAT(S2Data,
                  HasSummaryData(LU_S_Id, TU2_S_S2_Data, TU2Resolution));
    }
  }
}

TEST_F(EntityLinkerTest, RejectsDuplicateTUSummary) {
  NestedBuildNamespace LUNamespace(
      {BuildNamespace(BuildNamespaceKind::LinkUnit, "LU")});

  EntityLinker Linker(LUNamespace);

  auto TU1 = createTUSummaryEncoding(BuildNamespaceKind::CompilationUnit, "TU");

  ASSERT_THAT_ERROR(Linker.link(std::move(TU1)), llvm::Succeeded());

  auto TU2 = createTUSummaryEncoding(BuildNamespaceKind::CompilationUnit, "TU");

  ASSERT_THAT_ERROR(Linker.link(std::move(TU2)),
                    llvm::FailedWithMessage(
                        HasSubstr("failed to link TU summary: duplicate "
                                  "BuildNamespace(CompilationUnit, TU)")));
}

// Reproduces a crash when linking internal-linkage entities
// (e.g. "static inline" functions) that share the same USR across TUs.
TEST_F(EntityLinkerTest, InternalLinkageWithEmptyNamespaceAcrossTUs) {
  constexpr auto LinkUnit = BuildNamespaceKind::LinkUnit;
  constexpr auto CompilationUnit = BuildNamespaceKind::CompilationUnit;
  EntityLinker Linker(NestedBuildNamespace{BuildNamespace(LinkUnit, "LU")});

  auto TU1 = createTUSummaryEncoding(CompilationUnit, "TU1");
  addEntity(*TU1, "some_static_inline", InternalLinkage);
  ASSERT_THAT_ERROR(Linker.link(std::move(TU1)), llvm::Succeeded());

  auto TU2 = createTUSummaryEncoding(CompilationUnit, "TU2");
  addEntity(*TU2, "some_static_inline", InternalLinkage);
  ASSERT_THAT_ERROR(Linker.link(std::move(TU2)), llvm::Succeeded());

  // Check that the two internal symbols are not merged.
  const auto Output = std::move(Linker).takeOutput();
  const auto &IdTable = getIdTable(Output);

  NestedBuildNamespace TU1NS{{{CompilationUnit, "TU1"}, {LinkUnit, "LU"}}};
  NestedBuildNamespace TU2NS{{{CompilationUnit, "TU2"}, {LinkUnit, "LU"}}};
  EntityName ExpectedTU1Name("some_static_inline", "", TU1NS);
  EntityName ExpectedTU2Name("some_static_inline", "", TU2NS);

  ASSERT_EQ(IdTable.count(), 2u);
  EXPECT_THAT(IdTable, ContainsEntity(ExpectedTU1Name));
  EXPECT_THAT(IdTable, ContainsEntity(ExpectedTU2Name));
}

} // namespace