lib/DebugInfo/PDB/Native/GlobalsStream.cpp

   1 //===- GlobalsStream.cpp - PDB Index of Symbols by Name ---------*- C++ -*-===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // The on-disk structores used in this file are based on the reference
  10 // implementation which is available at
  11 // https://github.com/Microsoft/microsoft-pdb/blob/master/PDB/dbi/gsi.h
  12 //
  13 // When you are reading the reference source code, you'd find the
  14 // information below useful.
  15 //
  16 //  - ppdb1->m_fMinimalDbgInfo seems to be always true.
  17 //  - SMALLBUCKETS macro is defined.
  18 //
  19 //===----------------------------------------------------------------------===//
  20
  21 #include "llvm/DebugInfo/PDB/Native/GlobalsStream.h"
  22
  23 #include "llvm/DebugInfo/CodeView/RecordName.h"
  24 #include "llvm/DebugInfo/PDB/Native/Hash.h"
  25 #include "llvm/DebugInfo/PDB/Native/RawError.h"
  26 #include "llvm/DebugInfo/PDB/Native/SymbolStream.h"
  27 #include "llvm/Support/BinaryStreamReader.h"
  28 #include "llvm/Support/Error.h"
  29 #include <algorithm>
  30
  31 using namespace llvm;
  32 using namespace llvm::msf;
  33 using namespace llvm::pdb;
  34
  35 GlobalsStream::GlobalsStream(std::unique_ptr<MappedBlockStream> Stream)
  36     : Stream(std::move(Stream)) {}
  37
  38 GlobalsStream::~GlobalsStream() = default;
  39
  40 Error GlobalsStream::reload() {
  41   BinaryStreamReader Reader(*Stream);
  42   if (auto E = GlobalsTable.read(Reader))
  43     return E;
  44   return Error::success();
  45 }
  46
  47 std::vector<std::pair<uint32_t, codeview::CVSymbol>>
  48 GlobalsStream::findRecordsByName(StringRef Name,
  49                                  const SymbolStream &Symbols) const {
  50   std::vector<std::pair<uint32_t, codeview::CVSymbol>> Result;
  51
  52   // Hash the name to figure out which bucket this goes into.
  53   size_t ExpandedBucketIndex = hashStringV1(Name) % IPHR_HASH;
  54   int32_t CompressedBucketIndex = GlobalsTable.BucketMap[ExpandedBucketIndex];
  55   if (CompressedBucketIndex == -1)
  56     return Result;
  57
  58   uint32_t LastBucketIndex = GlobalsTable.HashBuckets.size() - 1;
  59   uint32_t StartRecordIndex =
  60       GlobalsTable.HashBuckets[CompressedBucketIndex] / 12;
  61   uint32_t EndRecordIndex = 0;
  62   if (LLVM_LIKELY(uint32_t(CompressedBucketIndex) < LastBucketIndex)) {
  63     EndRecordIndex = GlobalsTable.HashBuckets[CompressedBucketIndex + 1];
  64   } else {
  65     // If this is the last bucket, it consists of all hash records until the end
  66     // of the HashRecords array.
  67     EndRecordIndex = GlobalsTable.HashRecords.size() * 12;
  68   }
  69
  70   EndRecordIndex /= 12;
  71
  72   assert(EndRecordIndex <= GlobalsTable.HashRecords.size());
  73   while (StartRecordIndex < EndRecordIndex) {
  74     PSHashRecord PSH = GlobalsTable.HashRecords[StartRecordIndex];
  75     uint32_t Off = PSH.Off - 1;
  76     codeview::CVSymbol Record = Symbols.readRecord(Off);
  77     if (codeview::getSymbolName(Record) == Name)
  78       Result.push_back(std::make_pair(Off, std::move(Record)));
  79     ++StartRecordIndex;
  80   }
  81   return Result;
  82 }
  83
  84 static Error checkHashHdrVersion(const GSIHashHeader *HashHdr) {
  85   if (HashHdr->VerHdr != GSIHashHeader::HdrVersion)
  86     return make_error<RawError>(
  87         raw_error_code::feature_unsupported,
  88         "Encountered unsupported globals stream version.");
  89
  90   return Error::success();
  91 }
  92
  93 static Error readGSIHashHeader(const GSIHashHeader *&HashHdr,
  94                                BinaryStreamReader &Reader) {
  95   if (Reader.readObject(HashHdr))
  96     return make_error<RawError>(raw_error_code::corrupt_file,
  97                                 "Stream does not contain a GSIHashHeader.");
  98
  99   if (HashHdr->VerSignature != GSIHashHeader::HdrSignature)
 100     return make_error<RawError>(
 101         raw_error_code::feature_unsupported,
 102         "GSIHashHeader signature (0xffffffff) not found.");
 103
 104   return Error::success();
 105 }
 106
 107 static Error readGSIHashRecords(FixedStreamArray<PSHashRecord> &HashRecords,
 108                                 const GSIHashHeader *HashHdr,
 109                                 BinaryStreamReader &Reader) {
 110   if (auto EC = checkHashHdrVersion(HashHdr))
 111     return EC;
 112
 113   // HashHdr->HrSize specifies the number of bytes of PSHashRecords we have.
 114   // Verify that we can read them all.
 115   if (HashHdr->HrSize % sizeof(PSHashRecord))
 116     return make_error<RawError>(raw_error_code::corrupt_file,
 117                                 "Invalid HR array size.");
 118   uint32_t NumHashRecords = HashHdr->HrSize / sizeof(PSHashRecord);
 119   if (auto EC = Reader.readArray(HashRecords, NumHashRecords))
 120     return joinErrors(std::move(EC),
 121                       make_error<RawError>(raw_error_code::corrupt_file,
 122                                            "Error reading hash records."));
 123
 124   return Error::success();
 125 }
 126
 127 static Error
 128 readGSIHashBuckets(FixedStreamArray<support::ulittle32_t> &HashBuckets,
 129                    FixedStreamArray<support::ulittle32_t> &HashBitmap,
 130                    const GSIHashHeader *HashHdr,
 131                    MutableArrayRef<int32_t> BucketMap,
 132                    BinaryStreamReader &Reader) {
 133   if (auto EC = checkHashHdrVersion(HashHdr))
 134     return EC;
 135
 136   // Before the actual hash buckets, there is a bitmap of length determined by
 137   // IPHR_HASH.
 138   size_t BitmapSizeInBits = alignTo(IPHR_HASH + 1, 32);
 139   uint32_t NumBitmapEntries = BitmapSizeInBits / 32;
 140   if (auto EC = Reader.readArray(HashBitmap, NumBitmapEntries))
 141     return joinErrors(std::move(EC),
 142                       make_error<RawError>(raw_error_code::corrupt_file,
 143                                            "Could not read a bitmap."));
 144   uint32_t NumBuckets1 = 0;
 145   uint32_t CompressedBucketIdx = 0;
 146   for (uint32_t I = 0; I <= IPHR_HASH; ++I) {
 147     uint8_t WordIdx = I / 32;
 148     uint8_t BitIdx = I % 32;
 149     bool IsSet = HashBitmap[WordIdx] & (1U << BitIdx);
 150     if (IsSet) {
 151       ++NumBuckets1;
 152       BucketMap[I] = CompressedBucketIdx++;
 153     } else {
 154       BucketMap[I] = -1;
 155     }
 156   }
 157
 158   uint32_t NumBuckets = 0;
 159   for (uint32_t B : HashBitmap)
 160     NumBuckets += countPopulation(B);
 161
 162   // Hash buckets follow.
 163   if (auto EC = Reader.readArray(HashBuckets, NumBuckets))
 164     return joinErrors(std::move(EC),
 165                       make_error<RawError>(raw_error_code::corrupt_file,
 166                                            "Hash buckets corrupted."));
 167
 168   return Error::success();
 169 }
 170
 171 Error GSIHashTable::read(BinaryStreamReader &Reader) {
 172   if (auto EC = readGSIHashHeader(HashHdr, Reader))
 173     return EC;
 174   if (auto EC = readGSIHashRecords(HashRecords, HashHdr, Reader))
 175     return EC;
 176   if (HashHdr->HrSize > 0)
 177     if (auto EC = readGSIHashBuckets(HashBuckets, HashBitmap, HashHdr,
 178                                      BucketMap, Reader))
 179       return EC;
 180   return Error::success();
 181 }