//===- llvm/unittest/DebugInfo/GSYMV2Test.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 "llvm/ADT/SmallString.h"
#include "llvm/DebugInfo/GSYM/FileWriter.h"
#include "llvm/DebugInfo/GSYM/FunctionInfo.h"
#include "llvm/DebugInfo/GSYM/GlobalData.h"
#include "llvm/DebugInfo/GSYM/GsymCreator.h"
#include "llvm/DebugInfo/GSYM/GsymCreatorV1.h"
#include "llvm/DebugInfo/GSYM/GsymCreatorV2.h"
#include "llvm/DebugInfo/GSYM/GsymDataExtractor.h"
#include "llvm/DebugInfo/GSYM/GsymReader.h"
#include "llvm/DebugInfo/GSYM/HeaderV2.h"
#include "llvm/DebugInfo/GSYM/InlineInfo.h"
#include "llvm/DebugInfo/GSYM/OutputAggregator.h"
#include "llvm/Support/Endian.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/Support/Path.h"
#include "llvm/Testing/Support/Error.h"

#include "gtest/gtest.h"
#include <string>

using namespace llvm;
using namespace gsym;

//===----------------------------------------------------------------------===//
// Creator V2 tests
//===----------------------------------------------------------------------===//

/// Helper functions

static void checkError(std::string ExpectedMsg, Error Err) {
  ASSERT_TRUE(bool(Err));
  handleAllErrors(std::move(Err), [&](const ErrorInfoBase &Actual) {
    EXPECT_EQ(Actual.message(), ExpectedMsg);
  });
}

/// Helper to encode a GsymCreatorV2 and return the raw bytes.
static Expected<SmallString<512>> encodeV2(const GsymCreatorV2 &GC,
                                           llvm::endianness ByteOrder) {
  SmallString<512> Str;
  raw_svector_ostream OutStrm(Str);
  FileWriter FW(OutStrm, ByteOrder);
  FW.setStringOffsetSize(GC.getStringOffsetSize());
  if (auto Err = GC.encode(FW))
    return std::move(Err);
  return Str;
}

/// Helper to decode the HeaderV2 from raw bytes.
static Expected<HeaderV2> decodeHeaderV2(StringRef Bytes,
                                         llvm::endianness ByteOrder) {
  GsymDataExtractor Data(Bytes, ByteOrder == llvm::endianness::little);
  return HeaderV2::decode(Data);
}

/// Helper to decode a GlobalData entry at a given offset.
static GlobalData decodeGlobalDataEntry(StringRef Bytes, uint64_t &Offset,
                                        llvm::endianness ByteOrder) {
  GsymDataExtractor Data(Bytes, ByteOrder == llvm::endianness::little);
  GlobalData GD;
  GD.Type = static_cast<GlobalInfoType>(Data.getU32(&Offset));
  GD.FileOffset = Data.getU64(&Offset);
  GD.FileSize = Data.getU64(&Offset);
  return GD;
}

/// Encode error tests

TEST(GSYMV2Test, TestCreatorV2DoubleFinalize) {
  GsymCreatorV2 GC;
  const uint32_t Name = GC.insertString("foo");
  GC.addFunctionInfo(FunctionInfo(0x1000, 0x100, Name));
  OutputAggregator Null(nullptr);
  Error Err = GC.finalize(Null);
  ASSERT_FALSE(bool(Err));
  Err = GC.finalize(Null);
  ASSERT_TRUE(bool(Err));
  checkError("already finalized", std::move(Err));
}

/// Header and GlobalData structure tests

/// Encode a V2 GSYM and verify the header fields and GlobalData layout.
static void TestV2HeaderAndGlobalData(llvm::endianness ByteOrder,
                                      uint64_t BaseAddr,
                                      uint8_t ExpectedAddrOffSize,
                                      uint32_t ExpectedNumAddresses,
                                      bool HasUUID) {
  GsymCreatorV2 GC;
  const uint32_t Func1Name = GC.insertString("foo");
  const uint32_t Func2Name = GC.insertString("bar");
  GC.addFunctionInfo(FunctionInfo(BaseAddr + 0x00, 0x10, Func1Name));
  GC.addFunctionInfo(FunctionInfo(BaseAddr + 0x20, 0x10, Func2Name));

  uint8_t UUID[] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16};
  if (HasUUID)
    GC.setUUID(UUID);

  OutputAggregator Null(nullptr);
  Error Err = GC.finalize(Null);
  ASSERT_FALSE(bool(Err));

  auto Result = encodeV2(GC, ByteOrder);
  ASSERT_THAT_EXPECTED(Result, Succeeded());
  StringRef Data = *Result;

  // Verify header.
  auto HdrOrErr = decodeHeaderV2(Data, ByteOrder);
  ASSERT_THAT_EXPECTED(HdrOrErr, Succeeded());
  const HeaderV2 &Hdr = *HdrOrErr;
  EXPECT_EQ(Hdr.Magic, GSYM_MAGIC);
  EXPECT_EQ(Hdr.Version, HeaderV2::getVersion());
  EXPECT_EQ(Hdr.BaseAddress, BaseAddr);
  EXPECT_EQ(Hdr.NumAddresses, ExpectedNumAddresses);
  EXPECT_EQ(Hdr.AddrOffSize, ExpectedAddrOffSize);
  EXPECT_EQ(Hdr.StrTableEncoding, StringTableEncoding::Default);

  // Decode GlobalData entries starting at offset 24 (after fixed header).
  uint64_t Offset = HeaderV2::getEncodedSize();
  bool FoundAddrOffsets = false;
  bool FoundAddrInfoOffsets = false;
  bool FoundStringTable = false;
  bool FoundFileTable = false;
  bool FoundFunctionInfo = false;
  bool FoundUUID = false;
  bool FoundEndOfList = false;

  while (Offset < Data.size()) {
    GlobalData GD = decodeGlobalDataEntry(Data, Offset, ByteOrder);

    switch (GD.Type) {
    case GlobalInfoType::EndOfList:
      EXPECT_EQ(GD.FileOffset, 0u);
      EXPECT_EQ(GD.FileSize, 0u);
      FoundEndOfList = true;
      break;
    case GlobalInfoType::AddrOffsets:
      EXPECT_EQ(GD.FileSize,
                ExpectedNumAddresses * (uint64_t)ExpectedAddrOffSize);
      EXPECT_GT(GD.FileOffset, 0u);
      FoundAddrOffsets = true;
      break;
    case GlobalInfoType::AddrInfoOffsets:
      EXPECT_EQ(GD.FileSize,
                ExpectedNumAddresses *
                    (uint64_t)HeaderV2::getAddressInfoOffsetSize());
      EXPECT_GT(GD.FileOffset, 0u);
      FoundAddrInfoOffsets = true;
      break;
    case GlobalInfoType::StringTable:
      EXPECT_GT(GD.FileSize, 0u);
      EXPECT_GT(GD.FileOffset, 0u);
      FoundStringTable = true;
      break;
    case GlobalInfoType::FileTable:
      EXPECT_GT(GD.FileSize, 0u);
      EXPECT_GT(GD.FileOffset, 0u);
      FoundFileTable = true;
      break;
    case GlobalInfoType::FunctionInfo:
      EXPECT_GT(GD.FileSize, 0u);
      EXPECT_GT(GD.FileOffset, 0u);
      FoundFunctionInfo = true;
      break;
    case GlobalInfoType::UUID:
      EXPECT_EQ(GD.FileSize, sizeof(UUID));
      EXPECT_GT(GD.FileOffset, 0u);
      FoundUUID = true;
      break;
    }
    if (FoundEndOfList)
      break;
  }

  EXPECT_TRUE(FoundAddrOffsets);
  EXPECT_TRUE(FoundAddrInfoOffsets);
  EXPECT_TRUE(FoundStringTable);
  EXPECT_TRUE(FoundFileTable);
  EXPECT_TRUE(FoundFunctionInfo);
  EXPECT_TRUE(FoundEndOfList);
  EXPECT_EQ(FoundUUID, HasUUID);

  // Verify that all section data fits within the encoded buffer.
  Offset = HeaderV2::getEncodedSize();
  while (Offset < Data.size()) {
    GlobalData GD = decodeGlobalDataEntry(Data, Offset, ByteOrder);
    if (GD.Type == GlobalInfoType::EndOfList)
      break;
    EXPECT_LE(GD.FileOffset + GD.FileSize, Data.size())
        << "Section type " << static_cast<uint32_t>(GD.Type)
        << " extends beyond buffer";
  }
}

TEST(GSYMV2Test, TestCreatorV2HeaderAndGlobalDataLittle) {
  TestV2HeaderAndGlobalData(llvm::endianness::little, 0x1000,
                            /*ExpectedAddrOffSize=*/1,
                            /*ExpectedNumAddresses=*/2,
                            /*HasUUID=*/true);
}

TEST(GSYMV2Test, TestCreatorV2HeaderAndGlobalDataBig) {
  TestV2HeaderAndGlobalData(llvm::endianness::big, 0x1000,
                            /*ExpectedAddrOffSize=*/1,
                            /*ExpectedNumAddresses=*/2,
                            /*HasUUID=*/true);
}

TEST(GSYMV2Test, TestCreatorV2HeaderAndGlobalDataNoUUID) {
  TestV2HeaderAndGlobalData(llvm::endianness::little, 0x1000,
                            /*ExpectedAddrOffSize=*/1,
                            /*ExpectedNumAddresses=*/2,
                            /*HasUUID=*/false);
}

/// AddrInfoOffsets verification

TEST(GSYMV2Test, TestCreatorV2AddrInfoOffsetsPointToFunctionInfo) {
  // Verify that each AddrInfoOffset entry (relative to FunctionInfo section)
  // points to a valid location within the FunctionInfo section.
  GsymCreatorV2 GC;
  const uint32_t Func1Name = GC.insertString("func_a");
  const uint32_t Func2Name = GC.insertString("func_b");
  const uint32_t Func3Name = GC.insertString("func_c");
  GC.addFunctionInfo(FunctionInfo(0x1000, 0x100, Func1Name));
  GC.addFunctionInfo(FunctionInfo(0x1100, 0x100, Func2Name));
  GC.addFunctionInfo(FunctionInfo(0x1200, 0x100, Func3Name));
  OutputAggregator Null(nullptr);
  Error Err = GC.finalize(Null);
  ASSERT_FALSE(bool(Err));

  auto Result = encodeV2(GC, llvm::endianness::little);
  ASSERT_THAT_EXPECTED(Result, Succeeded());
  StringRef Bytes = *Result;

  constexpr uint8_t AddrInfoOffSize = HeaderV2::getAddressInfoOffsetSize();

  // Find the AddrInfoOffsets and FunctionInfo sections from GlobalData.
  uint64_t Offset = HeaderV2::getEncodedSize();
  uint64_t AIOffsetsOffset = 0;
  uint64_t FISize = 0;
  while (Offset < Bytes.size()) {
    GlobalData GD =
        decodeGlobalDataEntry(Bytes, Offset, llvm::endianness::little);
    if (GD.Type == GlobalInfoType::AddrInfoOffsets) {
      AIOffsetsOffset = GD.FileOffset;
    } else if (GD.Type == GlobalInfoType::FunctionInfo) {
      FISize = GD.FileSize;
    } else if (GD.Type == GlobalInfoType::EndOfList) {
      break;
    }
  }
  ASSERT_GT(AIOffsetsOffset, 0u);
  ASSERT_GT(FISize, 0u);

  // Each AddrInfoOffset is relative to the FunctionInfo section and should
  // be within [0, FISize).
  GsymDataExtractor Data(Bytes, /*IsLittleEndian=*/true);
  uint64_t AIOffset = AIOffsetsOffset;
  for (uint32_t I = 0; I < 3; ++I) {
    uint64_t RelOff = Data.getUnsigned(&AIOffset, AddrInfoOffSize);
    EXPECT_LT(RelOff, FISize)
        << "AddrInfoOffset[" << I << "] beyond FunctionInfo section";
  }

  // Relative offsets should be strictly increasing (sorted functions).
  AIOffset = AIOffsetsOffset;
  uint64_t PrevOff = Data.getUnsigned(&AIOffset, AddrInfoOffSize);
  EXPECT_EQ(PrevOff, 0u) << "First AddrInfoOffset should be 0";
  for (uint32_t I = 1; I < 3; ++I) {
    uint64_t CurOff = Data.getUnsigned(&AIOffset, AddrInfoOffSize);
    EXPECT_GT(CurOff, PrevOff)
        << "AddrInfoOffset[" << I << "] not strictly increasing";
    PrevOff = CurOff;
  }
}

/// UUID section verification

TEST(GSYMV2Test, TestCreatorV2UUIDSection) {
  GsymCreatorV2 GC;
  const uint32_t Name = GC.insertString("main");
  GC.addFunctionInfo(FunctionInfo(0x1000, 0x100, Name));
  uint8_t UUID[] = {0xAA, 0xBB, 0xCC, 0xDD, 0x11, 0x22, 0x33, 0x44};
  GC.setUUID(UUID);
  OutputAggregator Null(nullptr);
  Error Err = GC.finalize(Null);
  ASSERT_FALSE(bool(Err));

  auto Result = encodeV2(GC, llvm::endianness::little);
  ASSERT_THAT_EXPECTED(Result, Succeeded());
  StringRef Data = *Result;

  // Find UUID section.
  uint64_t Offset = HeaderV2::getEncodedSize();
  uint64_t UUIDOffset = 0, UUIDSize = 0;
  while (Offset < Data.size()) {
    GlobalData GD =
        decodeGlobalDataEntry(Data, Offset, llvm::endianness::little);
    if (GD.Type == GlobalInfoType::UUID) {
      UUIDOffset = GD.FileOffset;
      UUIDSize = GD.FileSize;
    } else if (GD.Type == GlobalInfoType::EndOfList) {
      break;
    }
  }
  ASSERT_EQ(UUIDSize, sizeof(UUID));
  ASSERT_GT(UUIDOffset, 0u);

  // Verify the UUID bytes match.
  StringRef UUIDData = Data.substr(UUIDOffset, UUIDSize);
  EXPECT_EQ(UUIDData,
            StringRef(reinterpret_cast<const char *>(UUID), sizeof(UUID)));
}

/// Verify that all sections in a V2 GSYM are correctly aligned.
/// Uses a 13-byte UUID and 8-byte AddrOffSize to create non-trivial
/// alignment scenarios where padding is required between sections.
TEST(GSYMV2Test, TestCreatorV2SectionAlignment) {
  // 13-byte UUID: after header (24) + GlobalData (7 entries * 20 = 140),
  // UUID ends at offset 177. AddrOffsets needs 8-byte alignment → 184.
  uint8_t UUID[] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13};
  GsymCreatorV2 GC;
  GC.setUUID(UUID);
  // Addresses far apart to force 8-byte AddrOffSize.
  GC.addFunctionInfo(FunctionInfo(0x1000, 0x100, GC.insertString("foo")));
  GC.addFunctionInfo(FunctionInfo(0x100001000, 0x100, GC.insertString("bar")));
  GC.addFunctionInfo(FunctionInfo(0x200002000, 0x100, GC.insertString("baz")));
  OutputAggregator Null(nullptr);
  ASSERT_FALSE(GC.finalize(Null));

  auto Result = encodeV2(GC, llvm::endianness::little);
  ASSERT_THAT_EXPECTED(Result, Succeeded());
  StringRef Data = *Result;

  // Decode header to get alignment sizes.
  auto HdrOrErr = decodeHeaderV2(Data, llvm::endianness::little);
  ASSERT_THAT_EXPECTED(HdrOrErr, Succeeded());
  const HeaderV2 &Hdr = *HdrOrErr;
  // Delta > UINT32_MAX rounds up to 8 (power-of-two only).
  EXPECT_EQ(Hdr.AddrOffSize, 8u);

  // Decode GlobalData entries and verify alignment for each section.
  uint64_t Offset = HeaderV2::getEncodedSize();
  while (Offset < Data.size()) {
    GlobalData GD =
        decodeGlobalDataEntry(Data, Offset, llvm::endianness::little);
    if (GD.Type == GlobalInfoType::EndOfList)
      break;
    switch (GD.Type) {
    case GlobalInfoType::UUID:
      // UUID has no alignment requirement.
      break;
    case GlobalInfoType::AddrOffsets:
      EXPECT_EQ(GD.FileOffset % Hdr.AddrOffSize, 0u)
          << "AddrOffsets not aligned to " << (unsigned)Hdr.AddrOffSize;
      break;
    case GlobalInfoType::AddrInfoOffsets:
      EXPECT_EQ(GD.FileOffset % HeaderV2::getAddressInfoOffsetSize(), 0u)
          << "AddrInfoOffsets not aligned to "
          << (unsigned)HeaderV2::getAddressInfoOffsetSize();
      break;
    case GlobalInfoType::FileTable:
      EXPECT_EQ(GD.FileOffset % 4, 0u) << "FileTable not 4-byte aligned";
      break;
    case GlobalInfoType::StringTable:
      // StringTable has no alignment requirement.
      break;
    case GlobalInfoType::FunctionInfo:
      EXPECT_EQ(GD.FileOffset % 4, 0u) << "FunctionInfo not 4-byte aligned";
      break;
    default:
      break;
    }
  }

  // Also verify the round-trip works.
  auto GROrErr = GsymReader::copyBuffer(Data);
  ASSERT_THAT_EXPECTED(GROrErr, Succeeded());
  EXPECT_EQ((*GROrErr)->getNumAddresses(), 3u);
}

//===----------------------------------------------------------------------===//
// Reader V2 tests (without creator — hand-crafted binary)
//===----------------------------------------------------------------------===//

/// Helper to build a minimal valid V2 GSYM binary in native endianness.
/// Creates one function "main" at BaseAddr with size FuncSize.
static SmallString<512> buildMinimalV2Binary(uint64_t BaseAddr,
                                             uint32_t FuncSize) {
  SmallString<512> Str;
  raw_svector_ostream OS(Str);
  FileWriter FW(OS, llvm::endianness::native);

  // We'll build: header (20) + GlobalData entries (6 entries * 20 = 120) +
  // sections. Total GlobalData entries: AddrOffsets, AddrInfoOffsets,
  // StringTable, FileTable, FunctionInfo, EndOfList = 6.
  constexpr uint64_t HeaderSize = HeaderV2::getEncodedSize();
  constexpr uint64_t NumGlobalEntries = 6;
  constexpr uint64_t GlobalDataSize = NumGlobalEntries * 20;
  constexpr uint8_t AddrOffSize = 1;
  constexpr uint8_t AddrInfoOffSize = HeaderV2::getAddressInfoOffsetSize();
  constexpr uint8_t StrpSize = HeaderV2::getStringOffsetSize();
  constexpr uint32_t NumAddresses = 1;

  // Layout sections sequentially after header + GlobalData.
  uint64_t CurOffset = HeaderSize + GlobalDataSize;

  // AddrOffsets: 1 address * 1 byte.
  const uint64_t AddrOffsetsOff = CurOffset;
  const uint64_t AddrOffsetsSize = NumAddresses * AddrOffSize;
  CurOffset += AddrOffsetsSize;

  // Pad to alignment for AddrInfoOffsets.
  CurOffset = llvm::alignTo(CurOffset, AddrInfoOffSize);
  const uint64_t AddrInfoOffsetsOff = CurOffset;
  const uint64_t AddrInfoOffsetsSize = NumAddresses * AddrInfoOffSize;
  CurOffset += AddrInfoOffsetsSize;

  // FileTable: 4 bytes (NumFiles=1) + 1 FileEntry (2 * StrpSize bytes).
  CurOffset = llvm::alignTo(CurOffset, 4);
  const uint64_t FileTableOff = CurOffset;
  const uint64_t FileTableSize = 4 + 2 * StrpSize; // 1 file entry.
  CurOffset += FileTableSize;

  // StringTable: "\0main\0" = 6 bytes.
  const uint64_t StringTableOff = CurOffset;
  const char StrTabData[] = "\0main";
  const uint64_t StringTableSize = sizeof(StrTabData); // includes trailing \0
  CurOffset += StringTableSize;

  // FunctionInfo: encode a minimal FunctionInfo.
  CurOffset = llvm::alignTo(CurOffset, 4);
  const uint64_t FuncInfoOff = CurOffset;
  // FunctionInfo encoding: uint32_t Size, uint32_t Name (strp offset).
  // "main" is at offset 1 in the string table.
  // Minimal FI: size (4 bytes) + name (4 bytes) = 8 bytes, no line table or
  // inline info (InfoType::EndOfList = 0 follows).
  // Actually FunctionInfo::encode writes: size, name, then info types.
  // Let's pre-encode a FunctionInfo to get exact bytes.
  SmallString<64> FIBuf;
  {
    raw_svector_ostream FIOS(FIBuf);
    FileWriter FIFW(FIOS, llvm::endianness::native);
    FIFW.setStringOffsetSize(HeaderV2::getStringOffsetSize());
    FunctionInfo FI(BaseAddr, FuncSize,
                    /*Name=*/1); // "main" at strtab offset 1
    auto OffOrErr = FI.encode(FIFW);
    assert(OffOrErr && "FunctionInfo encode failed");
    (void)OffOrErr;
  }
  const uint64_t FuncInfoSize = FIBuf.size();

  // Write header.
  FW.writeU32(GSYM_MAGIC);             // Magic
  FW.writeU16(HeaderV2::getVersion()); // Version
  FW.writeU8(AddrOffSize);             // AddrOffSize
  FW.writeU8(0);                       // StrTableEncoding
  FW.writeU64(BaseAddr);               // BaseAddress
  FW.writeU32(NumAddresses);           // NumAddresses

  // GlobalData entries.
  auto writeGD = [&](GlobalInfoType Type, uint64_t Off, uint64_t Size) {
    FW.writeU32(static_cast<uint32_t>(Type));
    FW.writeU64(Off);
    FW.writeU64(Size);
  };
  writeGD(GlobalInfoType::AddrOffsets, AddrOffsetsOff, AddrOffsetsSize);
  writeGD(GlobalInfoType::AddrInfoOffsets, AddrInfoOffsetsOff,
          AddrInfoOffsetsSize);
  writeGD(GlobalInfoType::StringTable, StringTableOff, StringTableSize);
  writeGD(GlobalInfoType::FileTable, FileTableOff, FileTableSize);
  writeGD(GlobalInfoType::FunctionInfo, FuncInfoOff, FuncInfoSize);
  writeGD(GlobalInfoType::EndOfList, 0, 0);

  // AddrOffsets section.
  assert(FW.tell() == AddrOffsetsOff);
  FW.writeU8(0); // Offset from BaseAddr = 0 for first function.

  // Pad to AddrInfoOffsets. Values are relative to FunctionInfo section.
  FW.alignTo(AddrInfoOffSize);
  assert(FW.tell() == AddrInfoOffsetsOff);
  FW.writeU64(0); // RelOff = 0 (first and only FunctionInfo).

  // FileTable.
  FW.alignTo(4);
  assert(FW.tell() == FileTableOff);
  FW.writeU32(1); // NumFiles = 1
  FW.writeU64(0); // File[0].Dir = 0
  FW.writeU64(0); // File[0].Base = 0

  // StringTable.
  assert(FW.tell() == StringTableOff);
  FW.writeData(ArrayRef<uint8_t>(reinterpret_cast<const uint8_t *>(StrTabData),
                                 StringTableSize));

  // FunctionInfo.
  FW.alignTo(4);
  assert(FW.tell() == FuncInfoOff);
  FW.writeData(ArrayRef<uint8_t>(
      reinterpret_cast<const uint8_t *>(FIBuf.data()), FIBuf.size()));

  return Str;
}

TEST(GSYMV2Test, TestReaderV2ParseHandCrafted) {
  // Build a minimal V2 binary by hand and verify the reader can parse it.
  auto Bytes = buildMinimalV2Binary(0x1000, 0x100);
  auto GROrErr = GsymReader::copyBuffer(StringRef(Bytes.data(), Bytes.size()));
  ASSERT_THAT_EXPECTED(GROrErr, Succeeded());
  auto &GR = *GROrErr;

  EXPECT_EQ(GR->getBaseAddress(), 0x1000u);
  EXPECT_EQ(GR->getNumAddresses(), 1u);
  EXPECT_EQ(GR->getAddressOffsetSize(), 1u);

  // Verify address lookup.
  auto Addr = GR->getAddress(0);
  ASSERT_TRUE(Addr.has_value());
  EXPECT_EQ(*Addr, 0x1000u);

  // Verify getString.
  EXPECT_EQ(GR->getString(1), "main");

  // Verify getFile (index 0 is the empty file entry).
  auto FE = GR->getFile(0);
  ASSERT_TRUE(FE.has_value());
  EXPECT_EQ(FE->Dir, 0u);
  EXPECT_EQ(FE->Base, 0u);
}

TEST(GSYMV2Test, TestReaderV2GetFunctionInfoHandCrafted) {
  auto Bytes = buildMinimalV2Binary(0x1000, 0x100);
  auto GROrErr = GsymReader::copyBuffer(StringRef(Bytes.data(), Bytes.size()));
  ASSERT_THAT_EXPECTED(GROrErr, Succeeded());
  auto &GR = *GROrErr;

  // getFunctionInfo should decode the function at 0x1000.
  auto FI = GR->getFunctionInfo(0x1000);
  ASSERT_THAT_EXPECTED(FI, Succeeded());
  EXPECT_EQ(FI->Range, AddressRange(0x1000, 0x1100));
  EXPECT_EQ(FI->Name, 1u); // "main" at strtab offset 1
  EXPECT_EQ(GR->getString(FI->Name), "main");

  // Address within the function range should also work.
  auto FI2 = GR->getFunctionInfo(0x1050);
  ASSERT_THAT_EXPECTED(FI2, Succeeded());
  EXPECT_EQ(FI2->Range, AddressRange(0x1000, 0x1100));

  // Address outside range should fail.
  auto FI3 = GR->getFunctionInfo(0x2000);
  EXPECT_THAT_EXPECTED(FI3, Failed());
}

TEST(GSYMV2Test, TestReaderV2LookupHandCrafted) {
  auto Bytes = buildMinimalV2Binary(0x1000, 0x100);
  auto GROrErr = GsymReader::copyBuffer(StringRef(Bytes.data(), Bytes.size()));
  ASSERT_THAT_EXPECTED(GROrErr, Succeeded());
  auto &GR = *GROrErr;

  // lookup should return a LookupResult.
  auto LR = GR->lookup(0x1000);
  ASSERT_THAT_EXPECTED(LR, Succeeded());
  EXPECT_EQ(LR->FuncName, "main");
  EXPECT_EQ(LR->FuncRange, AddressRange(0x1000, 0x1100));

  // lookup within range.
  auto LR2 = GR->lookup(0x1080);
  ASSERT_THAT_EXPECTED(LR2, Succeeded());
  EXPECT_EQ(LR2->FuncName, "main");

  // lookup outside range.
  auto LR3 = GR->lookup(0x2000);
  EXPECT_THAT_EXPECTED(LR3, Failed());
}

TEST(GSYMV2Test, TestReaderV2InvalidMagic) {
  // Create a buffer with invalid magic.
  char Buf[24] = {};
  Buf[0] = 'X'; // Bad magic.
  auto GR = GsymReader::copyBuffer(StringRef(Buf, sizeof(Buf)));
  EXPECT_THAT_EXPECTED(GR, Failed());
}

TEST(GSYMV2Test, TestReaderV2TooSmall) {
  // Buffer smaller than header.
  char Buf[10] = {};
  auto GR = GsymReader::copyBuffer(StringRef(Buf, sizeof(Buf)));
  EXPECT_THAT_EXPECTED(GR, Failed());
}

TEST(GSYMV2Test, TestReaderV2TruncatedFileTable) {
  // Build a valid V2 binary, then truncate the file table by reducing its
  // GlobalData FileSize. The reader should report the file table is too small.
  auto Bytes = buildMinimalV2Binary(0x1000, 0x100);
  // The binary has 1 file entry. Find the FileTable GlobalData entry and
  // shrink its FileSize to be too small.
  // GlobalData entries start at offset 24 (after HeaderV2).
  // Each entry is 20 bytes: Type(4) + FileOffset(8) + FileSize(8).
  // We need to find the FileTable entry and modify its FileSize.
  GsymDataExtractor Data(StringRef(Bytes.data(), Bytes.size()),
                         llvm::endianness::native == llvm::endianness::little);
  uint64_t Offset = HeaderV2::getEncodedSize();
  while (Offset < Bytes.size()) {
    uint64_t EntryOffset = Offset;
    uint32_t Type = Data.getU32(&Offset);
    uint64_t FileOffset = Data.getU64(&Offset);
    uint64_t FileSize = Data.getU64(&Offset);
    (void)FileOffset;
    (void)FileSize;
    if (Type == static_cast<uint32_t>(GlobalInfoType::FileTable)) {
      // Set FileSize to 4 (just the NumFiles field, no room for entries).
      // FileSize is at EntryOffset + 4 (Type) + 8 (FileOffset) = +12.
      uint64_t FileSizeOffset = EntryOffset + 12;
      support::endian::write64(Bytes.data() + FileSizeOffset, 4,
                               llvm::endianness::native);
      break;
    }
    if (Type == static_cast<uint32_t>(GlobalInfoType::EndOfList))
      break;
  }
  auto GR = GsymReader::copyBuffer(StringRef(Bytes.data(), Bytes.size()));
  ASSERT_FALSE(bool(GR));
  std::string ErrMsg;
  handleAllErrors(GR.takeError(),
                  [&](const ErrorInfoBase &E) { ErrMsg = E.message(); });
  EXPECT_NE(ErrMsg.find("FileTable section too small"), std::string::npos)
      << "Unexpected error: " << ErrMsg;
}

//===----------------------------------------------------------------------===//
// Creator/reader round-trip tests: Creator V2 -> Reader V2
//===----------------------------------------------------------------------===//

/// Helper to create, finalize, encode with GsymCreatorV2, then decode with
/// GsymReaderV2 and return the reader.
static Expected<std::unique_ptr<GsymReader>>
createAndReadV2(GsymCreatorV2 &GC,
                llvm::endianness ByteOrder = llvm::endianness::native) {
  OutputAggregator Null(nullptr);
  if (auto Err = GC.finalize(Null))
    return std::move(Err);

  SmallString<512> Str;
  raw_svector_ostream OutStrm(Str);
  FileWriter FW(OutStrm, ByteOrder);
  FW.setStringOffsetSize(GC.getStringOffsetSize());
  if (auto Err = GC.encode(FW))
    return std::move(Err);

  return GsymReader::copyBuffer(OutStrm.str());
}

TEST(GSYMV2Test, TestRoundTripGetFunctionInfoAtIndex) {
  GsymCreatorV2 GC;
  const uint32_t Name1 = GC.insertString("func_x");
  const uint32_t Name2 = GC.insertString("func_y");
  GC.addFunctionInfo(FunctionInfo(0x3000, 0x100, Name1));
  GC.addFunctionInfo(FunctionInfo(0x3100, 0x100, Name2));

  auto GROrErr = createAndReadV2(GC);
  ASSERT_THAT_EXPECTED(GROrErr, Succeeded());
  auto &GR = *GROrErr;

  // Access by index.
  auto FI0 = GR->getFunctionInfoAtIndex(0);
  ASSERT_THAT_EXPECTED(FI0, Succeeded());
  EXPECT_EQ(GR->getString(FI0->Name), "func_x");

  auto FI1 = GR->getFunctionInfoAtIndex(1);
  ASSERT_THAT_EXPECTED(FI1, Succeeded());
  EXPECT_EQ(GR->getString(FI1->Name), "func_y");

  // Out of bounds index.
  auto FI2 = GR->getFunctionInfoAtIndex(2);
  EXPECT_THAT_EXPECTED(FI2, Failed());
}

TEST(GSYMV2Test, TestRoundTripAddressTable) {
  GsymCreatorV2 GC;
  const uint32_t N1 = GC.insertString("a");
  const uint32_t N2 = GC.insertString("b");
  const uint32_t N3 = GC.insertString("c");
  GC.addFunctionInfo(FunctionInfo(0x8000, 0x10, N1));
  GC.addFunctionInfo(FunctionInfo(0x8020, 0x10, N2));
  GC.addFunctionInfo(FunctionInfo(0x8040, 0x10, N3));

  auto GROrErr = createAndReadV2(GC);
  ASSERT_THAT_EXPECTED(GROrErr, Succeeded());
  auto &GR = *GROrErr;

  // Verify addresses via getAddress.
  EXPECT_EQ(GR->getAddress(0), std::optional<uint64_t>(0x8000u));
  EXPECT_EQ(GR->getAddress(1), std::optional<uint64_t>(0x8020u));
  EXPECT_EQ(GR->getAddress(2), std::optional<uint64_t>(0x8040u));
  EXPECT_EQ(GR->getAddress(3), std::nullopt); // Out of bounds.
}

TEST(GSYMV2Test, TestRoundTripLargeAddressOffsets) {
  // Test with address offsets that require more than 2 bytes (rounds up to 4).
  GsymCreatorV2 GC;
  const uint32_t N1 = GC.insertString("near");
  const uint32_t N2 = GC.insertString("far");
  GC.addFunctionInfo(FunctionInfo(0x1000, 0x10, N1));
  GC.addFunctionInfo(FunctionInfo(0x1000 + 0x20000, 0x10, N2));

  auto GROrErr = createAndReadV2(GC);
  ASSERT_THAT_EXPECTED(GROrErr, Succeeded());
  auto &GR = *GROrErr;

  // V2 only supports power-of-two AddrOffSize (1/2/4/8), so 3 rounds up to 4.
  EXPECT_EQ(GR->getAddressOffsetSize(), 4u);
  EXPECT_EQ(GR->getNumAddresses(), 2u);

  auto FI1 = GR->getFunctionInfo(0x1000);
  ASSERT_THAT_EXPECTED(FI1, Succeeded());
  EXPECT_EQ(GR->getString(FI1->Name), "near");

  auto FI2 = GR->getFunctionInfo(0x1000 + 0x20000);
  ASSERT_THAT_EXPECTED(FI2, Succeeded());
  EXPECT_EQ(GR->getString(FI2->Name), "far");
}

/// Swapped-endianness round-trip tests

/// Get the non-native byte order.
static llvm::endianness swappedEndianness() {
  if constexpr (llvm::endianness::native == llvm::endianness::little)
    return llvm::endianness::big;
  else
    return llvm::endianness::little;
}

TEST(GSYMV2Test, TestRoundTripSwappedSingleFunction) {
  GsymCreatorV2 GC;
  const uint32_t Name = GC.insertString("hello");
  GC.addFunctionInfo(FunctionInfo(0x2000, 0x200, Name));

  auto GROrErr = createAndReadV2(GC, swappedEndianness());
  ASSERT_THAT_EXPECTED(GROrErr, Succeeded());
  auto &GR = *GROrErr;

  EXPECT_EQ(GR->getNumAddresses(), 1u);
  EXPECT_EQ(GR->getBaseAddress(), 0x2000u);

  auto FI = GR->getFunctionInfo(0x2000);
  ASSERT_THAT_EXPECTED(FI, Succeeded());
  EXPECT_EQ(FI->Range, AddressRange(0x2000, 0x2200));
  EXPECT_EQ(GR->getString(FI->Name), "hello");
}

TEST(GSYMV2Test, TestRoundTripSwappedMultipleFunctions) {
  GsymCreatorV2 GC;
  const uint32_t Name1 = GC.insertString("alpha");
  const uint32_t Name2 = GC.insertString("beta");
  const uint32_t Name3 = GC.insertString("gamma");
  GC.addFunctionInfo(FunctionInfo(0x1000, 0x100, Name1));
  GC.addFunctionInfo(FunctionInfo(0x1100, 0x100, Name2));
  GC.addFunctionInfo(FunctionInfo(0x1200, 0x100, Name3));

  auto GROrErr = createAndReadV2(GC, swappedEndianness());
  ASSERT_THAT_EXPECTED(GROrErr, Succeeded());
  auto &GR = *GROrErr;

  EXPECT_EQ(GR->getNumAddresses(), 3u);

  auto FI1 = GR->getFunctionInfo(0x1000);
  ASSERT_THAT_EXPECTED(FI1, Succeeded());
  EXPECT_EQ(GR->getString(FI1->Name), "alpha");

  auto FI2 = GR->getFunctionInfo(0x1100);
  ASSERT_THAT_EXPECTED(FI2, Succeeded());
  EXPECT_EQ(GR->getString(FI2->Name), "beta");

  auto FI3 = GR->getFunctionInfo(0x1200);
  ASSERT_THAT_EXPECTED(FI3, Succeeded());
  EXPECT_EQ(GR->getString(FI3->Name), "gamma");
}

TEST(GSYMV2Test, TestRoundTripSwappedLookup) {
  GsymCreatorV2 GC;
  const uint32_t Name1 = GC.insertString("start");
  const uint32_t Name2 = GC.insertString("end");
  GC.addFunctionInfo(FunctionInfo(0x5000, 0x500, Name1));
  GC.addFunctionInfo(FunctionInfo(0x5500, 0x500, Name2));

  auto GROrErr = createAndReadV2(GC, swappedEndianness());
  ASSERT_THAT_EXPECTED(GROrErr, Succeeded());
  auto &GR = *GROrErr;

  auto LR1 = GR->lookup(0x5000);
  ASSERT_THAT_EXPECTED(LR1, Succeeded());
  EXPECT_EQ(LR1->FuncName, "start");
  EXPECT_EQ(LR1->FuncRange, AddressRange(0x5000, 0x5500));

  auto LR2 = GR->lookup(0x5500);
  ASSERT_THAT_EXPECTED(LR2, Succeeded());
  EXPECT_EQ(LR2->FuncName, "end");

  auto LR3 = GR->lookup(0x5100);
  ASSERT_THAT_EXPECTED(LR3, Succeeded());
  EXPECT_EQ(LR3->FuncName, "start");

  auto LR4 = GR->lookup(0x6000);
  EXPECT_THAT_EXPECTED(LR4, Failed());
}

TEST(GSYMV2Test, TestRoundTripSwappedAddressTable) {
  GsymCreatorV2 GC;
  const uint32_t N1 = GC.insertString("a");
  const uint32_t N2 = GC.insertString("b");
  const uint32_t N3 = GC.insertString("c");
  GC.addFunctionInfo(FunctionInfo(0x8000, 0x10, N1));
  GC.addFunctionInfo(FunctionInfo(0x8020, 0x10, N2));
  GC.addFunctionInfo(FunctionInfo(0x8040, 0x10, N3));

  auto GROrErr = createAndReadV2(GC, swappedEndianness());
  ASSERT_THAT_EXPECTED(GROrErr, Succeeded());
  auto &GR = *GROrErr;

  EXPECT_EQ(GR->getAddress(0), std::optional<uint64_t>(0x8000u));
  EXPECT_EQ(GR->getAddress(1), std::optional<uint64_t>(0x8020u));
  EXPECT_EQ(GR->getAddress(2), std::optional<uint64_t>(0x8040u));
  EXPECT_EQ(GR->getAddress(3), std::nullopt);
}

//===----------------------------------------------------------------------===//
// Version round-trip tests: V1 -> V2 -> V1 and V2 -> V1 -> V2
//===----------------------------------------------------------------------===//

/// Recursively re-insert inline info strings and files from a reader into a
/// creator.
static void fixupInlineInfoForTransfer(const GsymReader &Reader,
                                       GsymCreator &Creator, InlineInfo &II) {
  II.Name = Creator.insertString(Reader.getString(II.Name));
  if (II.CallFile != 0) {
    if (auto FE = Reader.getFile(II.CallFile)) {
      StringRef Dir = Reader.getString(FE->Dir);
      StringRef Base = Reader.getString(FE->Base);
      SmallString<128> Path;
      if (!Dir.empty()) {
        Path = Dir;
        llvm::sys::path::append(Path, Base);
      } else {
        Path = Base;
      }
      II.CallFile = Creator.insertFile(Path);
    }
  }
  for (auto &Child : II.Children)
    fixupInlineInfoForTransfer(Reader, Creator, Child);
}

/// Transfer all function infos from a reader into a creator, re-inserting
/// all strings and files so that offsets are valid in the new creator.
static void transferFunctions(const GsymReader &Reader, GsymCreator &Creator) {
  for (uint32_t I = 0; I < Reader.getNumAddresses(); ++I) {
    auto FI = Reader.getFunctionInfoAtIndex(I);
    ASSERT_THAT_EXPECTED(FI, Succeeded());

    // Re-insert function name.
    FI->Name = Creator.insertString(Reader.getString(FI->Name));

    // Re-insert line table file entries.
    if (FI->OptLineTable) {
      for (size_t J = 0; J < FI->OptLineTable->size(); ++J) {
        LineEntry &LE = FI->OptLineTable->get(J);
        if (LE.File != 0) {
          if (auto FE = Reader.getFile(LE.File)) {
            StringRef Dir = Reader.getString(FE->Dir);
            StringRef Base = Reader.getString(FE->Base);
            SmallString<128> Path;
            if (!Dir.empty()) {
              Path = Dir;
              llvm::sys::path::append(Path, Base);
            } else {
              Path = Base;
            }
            LE.File = Creator.insertFile(Path);
          }
        }
      }
    }

    // Re-insert inline info strings and files.
    if (FI->Inline)
      fixupInlineInfoForTransfer(Reader, Creator, *FI->Inline);

    Creator.addFunctionInfo(std::move(*FI));
  }
}

/// Encode a GsymCreator to bytes.
static SmallString<1024> encodeCreator(const GsymCreator &GC) {
  SmallString<1024> Str;
  raw_svector_ostream OS(Str);
  FileWriter FW(OS, llvm::endianness::native);
  FW.setStringOffsetSize(GC.getStringOffsetSize());
  llvm::Error Err = GC.encode(FW);
  EXPECT_FALSE(bool(Err));
  return Str;
}

/// Collect lookup results for a set of addresses from a reader.
static std::vector<LookupResult> collectLookups(const GsymReader &Reader,
                                                ArrayRef<uint64_t> Addrs) {
  std::vector<LookupResult> Results;
  for (auto Addr : Addrs) {
    auto LR = Reader.lookup(Addr);
    EXPECT_TRUE(bool(LR));
    if (LR)
      Results.push_back(std::move(*LR));
  }
  return Results;
}

TEST(GSYMV2Test, TestVersionRoundTripV1ToV2ToV1) {
  // Create a V1 GSYM with line tables and inline info.
  GsymCreatorV1 GC1;
  FunctionInfo FI(0x1000, 0x100, GC1.insertString("main"));
  FI.OptLineTable = LineTable();
  const uint32_t MainFile = GC1.insertFile("/tmp/main.c");
  const uint32_t FooFile = GC1.insertFile("/tmp/foo.h");
  FI.OptLineTable->push(LineEntry(0x1000, MainFile, 5));
  FI.OptLineTable->push(LineEntry(0x1010, FooFile, 10));
  FI.OptLineTable->push(LineEntry(0x1020, MainFile, 8));
  FI.Inline = InlineInfo();
  FI.Inline->Name = GC1.insertString("inlined_func");
  FI.Inline->CallFile = MainFile;
  FI.Inline->CallLine = 6;
  FI.Inline->Ranges.insert(AddressRange(0x1010, 0x1020));
  InlineInfo NestedInline;
  NestedInline.Name = GC1.insertString("deep_inline");
  NestedInline.CallFile = FooFile;
  NestedInline.CallLine = 33;
  NestedInline.Ranges.insert(AddressRange(0x1012, 0x1018));
  FI.Inline->Children.emplace_back(NestedInline);
  GC1.addFunctionInfo(std::move(FI));

  FunctionInfo FI2(0x1100, 0x50, GC1.insertString("helper"));
  FI2.OptLineTable = LineTable();
  FI2.OptLineTable->push(LineEntry(0x1100, MainFile, 20));
  FI2.OptLineTable->push(LineEntry(0x1120, MainFile, 25));
  GC1.addFunctionInfo(std::move(FI2));

  OutputAggregator Null(nullptr);
  ASSERT_FALSE(bool(GC1.finalize(Null)));
  SmallString<1024> OrigV1Bytes = encodeCreator(GC1);
  ASSERT_GT(OrigV1Bytes.size(), 0u);

  // Read original V1.
  auto OrigReaderOrErr = GsymReader::copyBuffer(OrigV1Bytes);
  ASSERT_THAT_EXPECTED(OrigReaderOrErr, Succeeded());
  auto &OrigReader = *OrigReaderOrErr;

  // Collect lookup results from original V1.
  std::vector<uint64_t> TestAddrs = {0x1000, 0x1008, 0x1010, 0x1012,
                                     0x1015, 0x1020, 0x1100, 0x1120};
  auto OrigResults = collectLookups(*OrigReader, TestAddrs);
  ASSERT_EQ(OrigResults.size(), TestAddrs.size());

  // Convert V1 → V2.
  GsymCreatorV2 GC2;
  transferFunctions(*OrigReader, GC2);
  ASSERT_FALSE(bool(GC2.finalize(Null)));
  SmallString<1024> V2Bytes = encodeCreator(GC2);
  ASSERT_GT(V2Bytes.size(), 0u);

  auto V2ReaderOrErr = GsymReader::copyBuffer(V2Bytes);
  ASSERT_THAT_EXPECTED(V2ReaderOrErr, Succeeded());
  auto &V2Reader = *V2ReaderOrErr;

  // Verify V2 lookups match original V1.
  auto V2Results = collectLookups(*V2Reader, TestAddrs);
  ASSERT_EQ(V2Results.size(), TestAddrs.size());
  for (size_t I = 0; I < TestAddrs.size(); ++I)
    EXPECT_EQ(V2Results[I], OrigResults[I])
        << "Mismatch at address " << TestAddrs[I] << " after V1->V2";

  // Convert V2 → V1.
  GsymCreatorV1 GC3;
  transferFunctions(*V2Reader, GC3);
  ASSERT_FALSE(bool(GC3.finalize(Null)));
  SmallString<1024> FinalV1Bytes = encodeCreator(GC3);
  ASSERT_GT(FinalV1Bytes.size(), 0u);

  auto FinalReaderOrErr = GsymReader::copyBuffer(FinalV1Bytes);
  ASSERT_THAT_EXPECTED(FinalReaderOrErr, Succeeded());
  auto &FinalReader = *FinalReaderOrErr;

  // Verify final V1 lookups match original V1.
  auto FinalResults = collectLookups(*FinalReader, TestAddrs);
  ASSERT_EQ(FinalResults.size(), TestAddrs.size());
  for (size_t I = 0; I < TestAddrs.size(); ++I)
    EXPECT_EQ(FinalResults[I], OrigResults[I])
        << "Mismatch at address " << TestAddrs[I] << " after V1->V2->V1";
}

TEST(GSYMV2Test, TestVersionRoundTripV2ToV1ToV2) {
  // Create a V2 GSYM with line tables and inline info.
  GsymCreatorV2 GC1;
  FunctionInfo FI(0x2000, 0x200, GC1.insertString("entry"));
  FI.OptLineTable = LineTable();
  const uint32_t SrcFile = GC1.insertFile("/src/app.cc");
  const uint32_t HdrFile = GC1.insertFile("/src/util.h");
  FI.OptLineTable->push(LineEntry(0x2000, SrcFile, 10));
  FI.OptLineTable->push(LineEntry(0x2040, HdrFile, 50));
  FI.OptLineTable->push(LineEntry(0x2080, HdrFile, 55));
  FI.OptLineTable->push(LineEntry(0x20C0, SrcFile, 15));
  FI.Inline = InlineInfo();
  FI.Inline->Name = GC1.insertString("util_helper");
  FI.Inline->CallFile = SrcFile;
  FI.Inline->CallLine = 11;
  FI.Inline->Ranges.insert(AddressRange(0x2040, 0x20C0));
  InlineInfo Child;
  Child.Name = GC1.insertString("util_detail");
  Child.CallFile = HdrFile;
  Child.CallLine = 52;
  Child.Ranges.insert(AddressRange(0x2080, 0x20A0));
  FI.Inline->Children.emplace_back(Child);
  GC1.addFunctionInfo(std::move(FI));

  FunctionInfo FI2(0x2200, 0x100, GC1.insertString("cleanup"));
  FI2.OptLineTable = LineTable();
  FI2.OptLineTable->push(LineEntry(0x2200, SrcFile, 30));
  FI2.OptLineTable->push(LineEntry(0x2250, SrcFile, 35));
  GC1.addFunctionInfo(std::move(FI2));

  OutputAggregator Null(nullptr);
  ASSERT_FALSE(bool(GC1.finalize(Null)));
  SmallString<1024> OrigV2Bytes = encodeCreator(GC1);
  ASSERT_GT(OrigV2Bytes.size(), 0u);

  // Read original V2.
  auto OrigReaderOrErr = GsymReader::copyBuffer(OrigV2Bytes);
  ASSERT_THAT_EXPECTED(OrigReaderOrErr, Succeeded());
  auto &OrigReader = *OrigReaderOrErr;

  // Collect lookup results from original V2.
  std::vector<uint64_t> TestAddrs = {0x2000, 0x2020, 0x2040, 0x2080,
                                     0x2090, 0x20C0, 0x2200, 0x2250};
  auto OrigResults = collectLookups(*OrigReader, TestAddrs);
  ASSERT_EQ(OrigResults.size(), TestAddrs.size());

  // Convert V2 → V1.
  GsymCreatorV1 GC2;
  transferFunctions(*OrigReader, GC2);
  ASSERT_FALSE(bool(GC2.finalize(Null)));
  SmallString<1024> V1Bytes = encodeCreator(GC2);
  ASSERT_GT(V1Bytes.size(), 0u);

  auto V1ReaderOrErr = GsymReader::copyBuffer(V1Bytes);
  ASSERT_THAT_EXPECTED(V1ReaderOrErr, Succeeded());
  auto &V1Reader = *V1ReaderOrErr;

  // Verify V1 lookups match original V2.
  auto V1Results = collectLookups(*V1Reader, TestAddrs);
  ASSERT_EQ(V1Results.size(), TestAddrs.size());
  for (size_t I = 0; I < TestAddrs.size(); ++I)
    EXPECT_EQ(V1Results[I], OrigResults[I])
        << "Mismatch at address " << TestAddrs[I] << " after V2->V1";

  // Convert V1 → V2.
  GsymCreatorV2 GC3;
  transferFunctions(*V1Reader, GC3);
  ASSERT_FALSE(bool(GC3.finalize(Null)));
  SmallString<1024> FinalV2Bytes = encodeCreator(GC3);
  ASSERT_GT(FinalV2Bytes.size(), 0u);

  auto FinalReaderOrErr = GsymReader::copyBuffer(FinalV2Bytes);
  ASSERT_THAT_EXPECTED(FinalReaderOrErr, Succeeded());
  auto &FinalReader = *FinalReaderOrErr;

  // Verify final V2 lookups match original V2.
  auto FinalResults = collectLookups(*FinalReader, TestAddrs);
  ASSERT_EQ(FinalResults.size(), TestAddrs.size());
  for (size_t I = 0; I < TestAddrs.size(); ++I)
    EXPECT_EQ(FinalResults[I], OrigResults[I])
        << "Mismatch at address " << TestAddrs[I] << " after V2->V1->V2";
}

//===----------------------------------------------------------------------===//
// Segmenting tests
//===----------------------------------------------------------------------===//

TEST(GSYMV2Test, TestV2SegmentingSize) {
  // Test that V2 segmenting produces segments whose actual encoded size
  // does not exceed the requested segment size. This catches bugs where
  // calculateHeaderAndTableSize() overestimates (e.g. using wrong
  // GlobalData entry size), causing segments to contain fewer functions
  // than they could.
  GsymCreatorV2 GC;
  const uint64_t BaseAddr = 0x1000;
  // Add 10 simple functions (no line table, minimal size).
  for (uint32_t I = 0; I < 10; ++I) {
    std::string Name = "f" + std::to_string(I);
    uint32_t NameOff = GC.insertString(Name);
    GC.addFunctionInfo(FunctionInfo(BaseAddr + I * 0x100, 0x100, NameOff));
  }
  OutputAggregator Null(nullptr);
  ASSERT_FALSE(GC.finalize(Null));

  // Create the first segment with a generous-but-bounded size.
  // We want a size that fits all 10 functions if the estimate is correct,
  // but might not fit all 10 if the estimate is too large.
  // First, encode the full GSYM to know the actual total size.
  SmallString<512> FullStr;
  raw_svector_ostream FullOS(FullStr);
  FileWriter FullFW(FullOS, llvm::endianness::native);
  FullFW.setStringOffsetSize(GC.getStringOffsetSize());
  ASSERT_FALSE(GC.encode(FullFW));
  const uint64_t FullSize = FullStr.size();

  // Use the full size as segment size — all functions should fit in one
  // segment. If calculateHeaderAndTableSize() overestimates, some functions
  // won't fit.
  size_t FuncIdx = 0;
  auto SegOrErr = GC.createSegment(FullSize, FuncIdx);
  ASSERT_THAT_EXPECTED(SegOrErr, Succeeded());
  ASSERT_NE(SegOrErr->get(), nullptr);
  // All or almost all functions should fit. The estimate may slightly
  // overestimate due to string/file table differences between the full
  // creator and the segment, but it should not be off by more than 1.
  EXPECT_GE(FuncIdx, 9u)
      << "Too few functions fit in segment — calculateHeaderAndTableSize() "
         "may be overestimating";
}