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📄 AppendingTypeTableBuilder.h(2.24 KB)
📄 CVRecord.h(4.16 KB)
📄 CVSymbolVisitor.h(1.23 KB)
📄 CVTypeVisitor.h(2.19 KB)
📄 CodeView.h(17.73 KB)
📄 CodeViewError.h(1.46 KB)
📄 CodeViewRecordIO.h(7.83 KB)
📄 CodeViewRegisters.def(16.43 KB)
📄 CodeViewSymbols.def(9.57 KB)
📄 CodeViewTypes.def(7.58 KB)
📄 ContinuationRecordBuilder.h(2.14 KB)
📄 DebugChecksumsSubsection.h(3.06 KB)
📄 DebugCrossExSubsection.h(2.1 KB)
📄 DebugCrossImpSubsection.h(2.76 KB)
📄 DebugFrameDataSubsection.h(2.02 KB)
📄 DebugInlineeLinesSubsection.h(3.86 KB)
📄 DebugLinesSubsection.h(4.77 KB)
📄 DebugStringTableSubsection.h(2.92 KB)
📄 DebugSubsection.h(1.43 KB)
📄 DebugSubsectionRecord.h(3.09 KB)
📄 DebugSubsectionVisitor.h(4.28 KB)
📄 DebugSymbolRVASubsection.h(1.83 KB)
📄 DebugSymbolsSubsection.h(1.6 KB)
📄 DebugUnknownSubsection.h(925 B)
📄 EnumTables.h(2.32 KB)
📄 Formatters.h(1.94 KB)
📄 FunctionId.h(1.34 KB)
📄 GUID.h(1.34 KB)
📄 GlobalTypeTableBuilder.h(4.39 KB)
📄 LazyRandomTypeCollection.h(4.64 KB)
📄 Line.h(3.57 KB)
📄 MergingTypeTableBuilder.h(2.71 KB)
📄 RecordName.h(809 B)
📄 RecordSerialization.h(7.07 KB)
📄 SimpleTypeSerializer.h(1.24 KB)
📄 StringsAndChecksums.h(3.92 KB)
📄 SymbolDeserializer.h(3.47 KB)
📄 SymbolDumpDelegate.h(1.18 KB)
📄 SymbolDumper.h(2.05 KB)
📄 SymbolRecord.h(27.67 KB)
📄 SymbolRecordHelpers.h(1.78 KB)
📄 SymbolRecordMapping.h(1.52 KB)
📄 SymbolSerializer.h(2.99 KB)
📄 SymbolVisitorCallbackPipeline.h(2.58 KB)
📄 SymbolVisitorCallbacks.h(1.81 KB)
📄 SymbolVisitorDelegate.h(1.02 KB)
📄 TypeCollection.h(1.35 KB)
📄 TypeDeserializer.h(5.47 KB)
📄 TypeDumpVisitor.h(3.26 KB)
📄 TypeHashing.h(8.75 KB)
📄 TypeIndex.h(9.64 KB)
📄 TypeIndexDiscovery.h(1.71 KB)
📄 TypeRecord.h(31.56 KB)
📄 TypeRecordHelpers.h(1.47 KB)
📄 TypeRecordMapping.h(1.97 KB)
📄 TypeStreamMerger.h(4.51 KB)
📄 TypeSymbolEmitter.h(884 B)
📄 TypeTableCollection.h(1.25 KB)
📄 TypeVisitorCallbackPipeline.h(3.74 KB)
📄 TypeVisitorCallbacks.h(2.67 KB)

Editing: TypeHashing.h

//===- TypeHashing.h ---------------------------------------------*- C++-*-===//
//
// 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
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_DEBUGINFO_CODEVIEW_TYPEHASHING_H
#define LLVM_DEBUGINFO_CODEVIEW_TYPEHASHING_H

#include "llvm/ADT/DenseMapInfo.h"
#include "llvm/ADT/Hashing.h"

#include "llvm/DebugInfo/CodeView/CodeView.h"
#include "llvm/DebugInfo/CodeView/TypeCollection.h"
#include "llvm/DebugInfo/CodeView/TypeIndex.h"

#include "llvm/Support/FormatProviders.h"

#include <type_traits>

namespace llvm {
namespace codeview {

/// A locally hashed type represents a straightforward hash code of a serialized
/// record.  The record is simply serialized, and then the bytes are hashed by
/// a standard algorithm.  This is sufficient for the case of de-duplicating
/// records within a single sequence of types, because if two records both have
/// a back-reference to the same type in the same stream, they will both have
/// the same numeric value for the TypeIndex of the back reference.
struct LocallyHashedType {
  hash_code Hash;
  ArrayRef<uint8_t> RecordData;

/// Given a type, compute its local hash.
  static LocallyHashedType hashType(ArrayRef<uint8_t> RecordData);

/// Given a sequence of types, compute all of the local hashes.
  template <typename Range>
  static std::vector<LocallyHashedType> hashTypes(Range &&Records) {
    std::vector<LocallyHashedType> Hashes;
    Hashes.reserve(std::distance(std::begin(Records), std::end(Records)));
    for (const auto &R : Records)
      Hashes.push_back(hashType(R));

return Hashes;
  }

static std::vector<LocallyHashedType>
  hashTypeCollection(TypeCollection &Types) {
    std::vector<LocallyHashedType> Hashes;
    Types.ForEachRecord([&Hashes](TypeIndex TI, const CVType &Type) {
      Hashes.push_back(hashType(Type.RecordData));
    });
    return Hashes;
  }
};

enum class GlobalTypeHashAlg : uint16_t {
  SHA1 = 0, // standard 20-byte SHA1 hash
  SHA1_8    // last 8-bytes of standard SHA1 hash
};

/// A globally hashed type represents a hash value that is sufficient to
/// uniquely identify a record across multiple type streams or type sequences.
/// This works by, for any given record A which references B, replacing the
/// TypeIndex that refers to B with a previously-computed global hash for B.  As
/// this is a recursive algorithm (e.g. the global hash of B also depends on the
/// global hashes of the types that B refers to), a global hash can uniquely
/// identify identify that A occurs in another stream that has a completely
/// different graph structure.  Although the hash itself is slower to compute,
/// probing is much faster with a globally hashed type, because the hash itself
/// is considered "as good as" the original type.  Since type records can be
/// quite large, this makes the equality comparison of the hash much faster than
/// equality comparison of a full record.
struct GloballyHashedType {
  GloballyHashedType() = default;
  GloballyHashedType(StringRef H)
      : GloballyHashedType(ArrayRef<uint8_t>(H.bytes_begin(), H.bytes_end())) {}
  GloballyHashedType(ArrayRef<uint8_t> H) {
    assert(H.size() == 8);
    ::memcpy(Hash.data(), H.data(), 8);
  }
  std::array<uint8_t, 8> Hash;

bool empty() const { return *(const uint64_t*)Hash.data() == 0; }

/// Given a sequence of bytes representing a record, compute a global hash for
  /// this record.  Due to the nature of global hashes incorporating the hashes
  /// of referenced records, this function requires a list of types and ids
  /// that RecordData might reference, indexable by TypeIndex.
  static GloballyHashedType hashType(ArrayRef<uint8_t> RecordData,
                                     ArrayRef<GloballyHashedType> PreviousTypes,
                                     ArrayRef<GloballyHashedType> PreviousIds);

/// Given a sequence of bytes representing a record, compute a global hash for
  /// this record.  Due to the nature of global hashes incorporating the hashes
  /// of referenced records, this function requires a list of types and ids
  /// that RecordData might reference, indexable by TypeIndex.
  static GloballyHashedType hashType(CVType Type,
                                     ArrayRef<GloballyHashedType> PreviousTypes,
                                     ArrayRef<GloballyHashedType> PreviousIds) {
    return hashType(Type.RecordData, PreviousTypes, PreviousIds);
  }

/// Given a sequence of combined type and ID records, compute global hashes
  /// for each of them, returning the results in a vector of hashed types.
  template <typename Range>
  static std::vector<GloballyHashedType> hashTypes(Range &&Records) {
    std::vector<GloballyHashedType> Hashes;
    bool UnresolvedRecords = false;
    for (const auto &R : Records) {
      GloballyHashedType H = hashType(R, Hashes, Hashes);
      if (H.empty())
        UnresolvedRecords = true;
      Hashes.push_back(H);
    }

// In some rare cases, there might be records with forward references in the
    // stream. Several passes might be needed to fully hash each record in the
    // Type stream. However this occurs on very small OBJs generated by MASM,
    // with a dozen records at most. Therefore this codepath isn't
    // time-critical, as it isn't taken in 99% of cases.
    while (UnresolvedRecords) {
      UnresolvedRecords = false;
      auto HashIt = Hashes.begin();
      for (const auto &R : Records) {
        if (HashIt->empty()) {
          GloballyHashedType H = hashType(R, Hashes, Hashes);
          if (H.empty())
            UnresolvedRecords = true;
          else
            *HashIt = H;
        }
        ++HashIt;
      }
    }

return Hashes;
  }

/// Given a sequence of combined type and ID records, compute global hashes
  /// for each of them, returning the results in a vector of hashed types.
  template <typename Range>
  static std::vector<GloballyHashedType>
  hashIds(Range &&Records, ArrayRef<GloballyHashedType> TypeHashes) {
    std::vector<GloballyHashedType> IdHashes;
    for (const auto &R : Records)
      IdHashes.push_back(hashType(R, TypeHashes, IdHashes));

return IdHashes;
  }

static std::vector<GloballyHashedType>
  hashTypeCollection(TypeCollection &Types) {
    std::vector<GloballyHashedType> Hashes;
    Types.ForEachRecord([&Hashes](TypeIndex TI, const CVType &Type) {
      Hashes.push_back(hashType(Type.RecordData, Hashes, Hashes));
    });
    return Hashes;
  }
};
#if defined(_MSC_VER)
// is_trivially_copyable is not available in older versions of libc++, but it is
// available in all supported versions of MSVC, so at least this gives us some
// coverage.
static_assert(std::is_trivially_copyable<GloballyHashedType>::value,
              "GloballyHashedType must be trivially copyable so that we can "
              "reinterpret_cast arrays of hash data to arrays of "
              "GloballyHashedType");
#endif
} // namespace codeview

template <> struct DenseMapInfo<codeview::LocallyHashedType> {
  static codeview::LocallyHashedType Empty;
  static codeview::LocallyHashedType Tombstone;

static codeview::LocallyHashedType getEmptyKey() { return Empty; }

static codeview::LocallyHashedType getTombstoneKey() { return Tombstone; }

static unsigned getHashValue(codeview::LocallyHashedType Val) {
    return Val.Hash;
  }

static bool isEqual(codeview::LocallyHashedType LHS,
                      codeview::LocallyHashedType RHS) {
    if (LHS.Hash != RHS.Hash)
      return false;
    return LHS.RecordData == RHS.RecordData;
  }
};

template <> struct DenseMapInfo<codeview::GloballyHashedType> {
  static codeview::GloballyHashedType Empty;
  static codeview::GloballyHashedType Tombstone;

static codeview::GloballyHashedType getEmptyKey() { return Empty; }

static codeview::GloballyHashedType getTombstoneKey() { return Tombstone; }

static unsigned getHashValue(codeview::GloballyHashedType Val) {
    return *reinterpret_cast<const unsigned *>(Val.Hash.data());
  }

static bool isEqual(codeview::GloballyHashedType LHS,
                      codeview::GloballyHashedType RHS) {
    return LHS.Hash == RHS.Hash;
  }
};

template <> struct format_provider<codeview::LocallyHashedType> {
public:
  static void format(const codeview::LocallyHashedType &V,
                     llvm::raw_ostream &Stream, StringRef Style) {
    write_hex(Stream, V.Hash, HexPrintStyle::Upper, 8);
  }
};

template <> struct format_provider<codeview::GloballyHashedType> {
public:
  static void format(const codeview::GloballyHashedType &V,
                     llvm::raw_ostream &Stream, StringRef Style) {
    for (uint8_t B : V.Hash) {
      write_hex(Stream, B, HexPrintStyle::Upper, 2);
    }
  }
};

} // namespace llvm

#endif

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