lib/DebugInfo/MSF/MSFBuilder.cpp

   1 //===- MSFBuilder.cpp -----------------------------------------------------===//
   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 #include "llvm/DebugInfo/MSF/MSFBuilder.h"
  10 #include "llvm/ADT/ArrayRef.h"
  11 #include "llvm/DebugInfo/MSF/MSFError.h"
  12 #include "llvm/DebugInfo/MSF/MappedBlockStream.h"
  13 #include "llvm/Support/BinaryByteStream.h"
  14 #include "llvm/Support/BinaryStreamWriter.h"
  15 #include "llvm/Support/Endian.h"
  16 #include "llvm/Support/Error.h"
  17 #include "llvm/Support/FileOutputBuffer.h"
  18 #include <algorithm>
  19 #include <cassert>
  20 #include <cstdint>
  21 #include <cstring>
  22 #include <memory>
  23 #include <utility>
  24 #include <vector>
  25
  26 using namespace llvm;
  27 using namespace llvm::msf;
  28 using namespace llvm::support;
  29
  30 static const uint32_t kSuperBlockBlock = 0;
  31 static const uint32_t kFreePageMap0Block = 1;
  32 static const uint32_t kFreePageMap1Block = 2;
  33 static const uint32_t kNumReservedPages = 3;
  34
  35 static const uint32_t kDefaultFreePageMap = kFreePageMap1Block;
  36 static const uint32_t kDefaultBlockMapAddr = kNumReservedPages;
  37
  38 MSFBuilder::MSFBuilder(uint32_t BlockSize, uint32_t MinBlockCount, bool CanGrow,
  39                        BumpPtrAllocator &Allocator)
  40     : Allocator(Allocator), IsGrowable(CanGrow),
  41       FreePageMap(kDefaultFreePageMap), BlockSize(BlockSize),
  42       BlockMapAddr(kDefaultBlockMapAddr), FreeBlocks(MinBlockCount, true) {
  43   FreeBlocks[kSuperBlockBlock] = false;
  44   FreeBlocks[kFreePageMap0Block] = false;
  45   FreeBlocks[kFreePageMap1Block] = false;
  46   FreeBlocks[BlockMapAddr] = false;
  47 }
  48
  49 Expected<MSFBuilder> MSFBuilder::create(BumpPtrAllocator &Allocator,
  50                                         uint32_t BlockSize,
  51                                         uint32_t MinBlockCount, bool CanGrow) {
  52   if (!isValidBlockSize(BlockSize))
  53     return make_error<MSFError>(msf_error_code::invalid_format,
  54                                 "The requested block size is unsupported");
  55
  56   return MSFBuilder(BlockSize,
  57                     std::max(MinBlockCount, msf::getMinimumBlockCount()),
  58                     CanGrow, Allocator);
  59 }
  60
  61 Error MSFBuilder::setBlockMapAddr(uint32_t Addr) {
  62   if (Addr == BlockMapAddr)
  63     return Error::success();
  64
  65   if (Addr >= FreeBlocks.size()) {
  66     if (!IsGrowable)
  67       return make_error<MSFError>(msf_error_code::insufficient_buffer,
  68                                   "Cannot grow the number of blocks");
  69     FreeBlocks.resize(Addr + 1, true);
  70   }
  71
  72   if (!isBlockFree(Addr))
  73     return make_error<MSFError>(
  74         msf_error_code::block_in_use,
  75         "Requested block map address is already in use");
  76   FreeBlocks[BlockMapAddr] = true;
  77   FreeBlocks[Addr] = false;
  78   BlockMapAddr = Addr;
  79   return Error::success();
  80 }
  81
  82 void MSFBuilder::setFreePageMap(uint32_t Fpm) { FreePageMap = Fpm; }
  83
  84 void MSFBuilder::setUnknown1(uint32_t Unk1) { Unknown1 = Unk1; }
  85
  86 Error MSFBuilder::setDirectoryBlocksHint(ArrayRef<uint32_t> DirBlocks) {
  87   for (auto B : DirectoryBlocks)
  88     FreeBlocks[B] = true;
  89   for (auto B : DirBlocks) {
  90     if (!isBlockFree(B)) {
  91       return make_error<MSFError>(msf_error_code::unspecified,
  92                                   "Attempt to reuse an allocated block");
  93     }
  94     FreeBlocks[B] = false;
  95   }
  96
  97   DirectoryBlocks = DirBlocks;
  98   return Error::success();
  99 }
 100
 101 Error MSFBuilder::allocateBlocks(uint32_t NumBlocks,
 102                                  MutableArrayRef<uint32_t> Blocks) {
 103   if (NumBlocks == 0)
 104     return Error::success();
 105
 106   uint32_t NumFreeBlocks = FreeBlocks.count();
 107   if (NumFreeBlocks < NumBlocks) {
 108     if (!IsGrowable)
 109       return make_error<MSFError>(msf_error_code::insufficient_buffer,
 110                                   "There are no free Blocks in the file");
 111     uint32_t AllocBlocks = NumBlocks - NumFreeBlocks;
 112     uint32_t OldBlockCount = FreeBlocks.size();
 113     uint32_t NewBlockCount = AllocBlocks + OldBlockCount;
 114     uint32_t NextFpmBlock = alignTo(OldBlockCount, BlockSize) + 1;
 115     FreeBlocks.resize(NewBlockCount, true);
 116     // If we crossed over an fpm page, we actually need to allocate 2 extra
 117     // blocks for each FPM group crossed and mark both blocks from the group as
 118     // used.  FPM blocks are marked as allocated regardless of whether or not
 119     // they ultimately describe the status of blocks in the file.  This means
 120     // that not only are extraneous blocks at the end of the main FPM marked as
 121     // allocated, but also blocks from the alternate FPM are always marked as
 122     // allocated.
 123     while (NextFpmBlock < NewBlockCount) {
 124       NewBlockCount += 2;
 125       FreeBlocks.resize(NewBlockCount, true);
 126       FreeBlocks.reset(NextFpmBlock, NextFpmBlock + 2);
 127       NextFpmBlock += BlockSize;
 128     }
 129   }
 130
 131   int I = 0;
 132   int Block = FreeBlocks.find_first();
 133   do {
 134     assert(Block != -1 && "We ran out of Blocks!");
 135
 136     uint32_t NextBlock = static_cast<uint32_t>(Block);
 137     Blocks[I++] = NextBlock;
 138     FreeBlocks.reset(NextBlock);
 139     Block = FreeBlocks.find_next(Block);
 140   } while (--NumBlocks > 0);
 141   return Error::success();
 142 }
 143
 144 uint32_t MSFBuilder::getNumUsedBlocks() const {
 145   return getTotalBlockCount() - getNumFreeBlocks();
 146 }
 147
 148 uint32_t MSFBuilder::getNumFreeBlocks() const { return FreeBlocks.count(); }
 149
 150 uint32_t MSFBuilder::getTotalBlockCount() const { return FreeBlocks.size(); }
 151
 152 bool MSFBuilder::isBlockFree(uint32_t Idx) const { return FreeBlocks[Idx]; }
 153
 154 Expected<uint32_t> MSFBuilder::addStream(uint32_t Size,
 155                                          ArrayRef<uint32_t> Blocks) {
 156   // Add a new stream mapped to the specified blocks.  Verify that the specified
 157   // blocks are both necessary and sufficient for holding the requested number
 158   // of bytes, and verify that all requested blocks are free.
 159   uint32_t ReqBlocks = bytesToBlocks(Size, BlockSize);
 160   if (ReqBlocks != Blocks.size())
 161     return make_error<MSFError>(
 162         msf_error_code::invalid_format,
 163         "Incorrect number of blocks for requested stream size");
 164   for (auto Block : Blocks) {
 165     if (Block >= FreeBlocks.size())
 166       FreeBlocks.resize(Block + 1, true);
 167
 168     if (!FreeBlocks.test(Block))
 169       return make_error<MSFError>(
 170           msf_error_code::unspecified,
 171           "Attempt to re-use an already allocated block");
 172   }
 173   // Mark all the blocks occupied by the new stream as not free.
 174   for (auto Block : Blocks) {
 175     FreeBlocks.reset(Block);
 176   }
 177   StreamData.push_back(std::make_pair(Size, Blocks));
 178   return StreamData.size() - 1;
 179 }
 180
 181 Expected<uint32_t> MSFBuilder::addStream(uint32_t Size) {
 182   uint32_t ReqBlocks = bytesToBlocks(Size, BlockSize);
 183   std::vector<uint32_t> NewBlocks;
 184   NewBlocks.resize(ReqBlocks);
 185   if (auto EC = allocateBlocks(ReqBlocks, NewBlocks))
 186     return std::move(EC);
 187   StreamData.push_back(std::make_pair(Size, NewBlocks));
 188   return StreamData.size() - 1;
 189 }
 190
 191 Error MSFBuilder::setStreamSize(uint32_t Idx, uint32_t Size) {
 192   uint32_t OldSize = getStreamSize(Idx);
 193   if (OldSize == Size)
 194     return Error::success();
 195
 196   uint32_t NewBlocks = bytesToBlocks(Size, BlockSize);
 197   uint32_t OldBlocks = bytesToBlocks(OldSize, BlockSize);
 198
 199   if (NewBlocks > OldBlocks) {
 200     uint32_t AddedBlocks = NewBlocks - OldBlocks;
 201     // If we're growing, we have to allocate new Blocks.
 202     std::vector<uint32_t> AddedBlockList;
 203     AddedBlockList.resize(AddedBlocks);
 204     if (auto EC = allocateBlocks(AddedBlocks, AddedBlockList))
 205       return EC;
 206     auto &CurrentBlocks = StreamData[Idx].second;
 207     CurrentBlocks.insert(CurrentBlocks.end(), AddedBlockList.begin(),
 208                          AddedBlockList.end());
 209   } else if (OldBlocks > NewBlocks) {
 210     // For shrinking, free all the Blocks in the Block map, update the stream
 211     // data, then shrink the directory.
 212     uint32_t RemovedBlocks = OldBlocks - NewBlocks;
 213     auto CurrentBlocks = ArrayRef<uint32_t>(StreamData[Idx].second);
 214     auto RemovedBlockList = CurrentBlocks.drop_front(NewBlocks);
 215     for (auto P : RemovedBlockList)
 216       FreeBlocks[P] = true;
 217     StreamData[Idx].second = CurrentBlocks.drop_back(RemovedBlocks);
 218   }
 219
 220   StreamData[Idx].first = Size;
 221   return Error::success();
 222 }
 223
 224 uint32_t MSFBuilder::getNumStreams() const { return StreamData.size(); }
 225
 226 uint32_t MSFBuilder::getStreamSize(uint32_t StreamIdx) const {
 227   return StreamData[StreamIdx].first;
 228 }
 229
 230 ArrayRef<uint32_t> MSFBuilder::getStreamBlocks(uint32_t StreamIdx) const {
 231   return StreamData[StreamIdx].second;
 232 }
 233
 234 uint32_t MSFBuilder::computeDirectoryByteSize() const {
 235   // The directory has the following layout, where each item is a ulittle32_t:
 236   //    NumStreams
 237   //    StreamSizes[NumStreams]
 238   //    StreamBlocks[NumStreams][]
 239   uint32_t Size = sizeof(ulittle32_t);             // NumStreams
 240   Size += StreamData.size() * sizeof(ulittle32_t); // StreamSizes
 241   for (const auto &D : StreamData) {
 242     uint32_t ExpectedNumBlocks = bytesToBlocks(D.first, BlockSize);
 243     assert(ExpectedNumBlocks == D.second.size() &&
 244            "Unexpected number of blocks");
 245     Size += ExpectedNumBlocks * sizeof(ulittle32_t);
 246   }
 247   return Size;
 248 }
 249
 250 Expected<MSFLayout> MSFBuilder::generateLayout() {
 251   SuperBlock *SB = Allocator.Allocate<SuperBlock>();
 252   MSFLayout L;
 253   L.SB = SB;
 254
 255   std::memcpy(SB->MagicBytes, Magic, sizeof(Magic));
 256   SB->BlockMapAddr = BlockMapAddr;
 257   SB->BlockSize = BlockSize;
 258   SB->NumDirectoryBytes = computeDirectoryByteSize();
 259   SB->FreeBlockMapBlock = FreePageMap;
 260   SB->Unknown1 = Unknown1;
 261
 262   uint32_t NumDirectoryBlocks = bytesToBlocks(SB->NumDirectoryBytes, BlockSize);
 263   if (NumDirectoryBlocks > DirectoryBlocks.size()) {
 264     // Our hint wasn't enough to satisfy the entire directory.  Allocate
 265     // remaining pages.
 266     std::vector<uint32_t> ExtraBlocks;
 267     uint32_t NumExtraBlocks = NumDirectoryBlocks - DirectoryBlocks.size();
 268     ExtraBlocks.resize(NumExtraBlocks);
 269     if (auto EC = allocateBlocks(NumExtraBlocks, ExtraBlocks))
 270       return std::move(EC);
 271     DirectoryBlocks.insert(DirectoryBlocks.end(), ExtraBlocks.begin(),
 272                            ExtraBlocks.end());
 273   } else if (NumDirectoryBlocks < DirectoryBlocks.size()) {
 274     uint32_t NumUnnecessaryBlocks = DirectoryBlocks.size() - NumDirectoryBlocks;
 275     for (auto B :
 276          ArrayRef<uint32_t>(DirectoryBlocks).drop_back(NumUnnecessaryBlocks))
 277       FreeBlocks[B] = true;
 278     DirectoryBlocks.resize(NumDirectoryBlocks);
 279   }
 280
 281   // Don't set the number of blocks in the file until after allocating Blocks
 282   // for the directory, since the allocation might cause the file to need to
 283   // grow.
 284   SB->NumBlocks = FreeBlocks.size();
 285
 286   ulittle32_t *DirBlocks = Allocator.Allocate<ulittle32_t>(NumDirectoryBlocks);
 287   std::uninitialized_copy_n(DirectoryBlocks.begin(), NumDirectoryBlocks,
 288                             DirBlocks);
 289   L.DirectoryBlocks = ArrayRef<ulittle32_t>(DirBlocks, NumDirectoryBlocks);
 290
 291   // The stream sizes should be re-allocated as a stable pointer and the stream
 292   // map should have each of its entries allocated as a separate stable pointer.
 293   if (!StreamData.empty()) {
 294     ulittle32_t *Sizes = Allocator.Allocate<ulittle32_t>(StreamData.size());
 295     L.StreamSizes = ArrayRef<ulittle32_t>(Sizes, StreamData.size());
 296     L.StreamMap.resize(StreamData.size());
 297     for (uint32_t I = 0; I < StreamData.size(); ++I) {
 298       Sizes[I] = StreamData[I].first;
 299       ulittle32_t *BlockList =
 300           Allocator.Allocate<ulittle32_t>(StreamData[I].second.size());
 301       std::uninitialized_copy_n(StreamData[I].second.begin(),
 302                                 StreamData[I].second.size(), BlockList);
 303       L.StreamMap[I] =
 304           ArrayRef<ulittle32_t>(BlockList, StreamData[I].second.size());
 305     }
 306   }
 307
 308   L.FreePageMap = FreeBlocks;
 309
 310   return L;
 311 }
 312
 313 static void commitFpm(WritableBinaryStream &MsfBuffer, const MSFLayout &Layout,
 314                       BumpPtrAllocator &Allocator) {
 315   auto FpmStream =
 316       WritableMappedBlockStream::createFpmStream(Layout, MsfBuffer, Allocator);
 317
 318   // We only need to create the alt fpm stream so that it gets initialized.
 319   WritableMappedBlockStream::createFpmStream(Layout, MsfBuffer, Allocator,
 320                                              true);
 321
 322   uint32_t BI = 0;
 323   BinaryStreamWriter FpmWriter(*FpmStream);
 324   while (BI < Layout.SB->NumBlocks) {
 325     uint8_t ThisByte = 0;
 326     for (uint32_t I = 0; I < 8; ++I) {
 327       bool IsFree =
 328           (BI < Layout.SB->NumBlocks) ? Layout.FreePageMap.test(BI) : true;
 329       uint8_t Mask = uint8_t(IsFree) << I;
 330       ThisByte |= Mask;
 331       ++BI;
 332     }
 333     cantFail(FpmWriter.writeObject(ThisByte));
 334   }
 335   assert(FpmWriter.bytesRemaining() == 0);
 336 }
 337
 338 Expected<FileBufferByteStream> MSFBuilder::commit(StringRef Path,
 339                                                   MSFLayout &Layout) {
 340   Expected<MSFLayout> L = generateLayout();
 341   if (!L)
 342     return L.takeError();
 343
 344   Layout = std::move(*L);
 345
 346   uint64_t FileSize = Layout.SB->BlockSize * Layout.SB->NumBlocks;
 347   auto OutFileOrError = FileOutputBuffer::create(Path, FileSize);
 348   if (auto EC = OutFileOrError.takeError())
 349     return std::move(EC);
 350
 351   FileBufferByteStream Buffer(std::move(*OutFileOrError),
 352                               llvm::support::little);
 353   BinaryStreamWriter Writer(Buffer);
 354
 355   if (auto EC = Writer.writeObject(*Layout.SB))
 356     return std::move(EC);
 357
 358   commitFpm(Buffer, Layout, Allocator);
 359
 360   uint32_t BlockMapOffset =
 361       msf::blockToOffset(Layout.SB->BlockMapAddr, Layout.SB->BlockSize);
 362   Writer.setOffset(BlockMapOffset);
 363   if (auto EC = Writer.writeArray(Layout.DirectoryBlocks))
 364     return std::move(EC);
 365
 366   auto DirStream = WritableMappedBlockStream::createDirectoryStream(
 367       Layout, Buffer, Allocator);
 368   BinaryStreamWriter DW(*DirStream);
 369   if (auto EC = DW.writeInteger<uint32_t>(Layout.StreamSizes.size()))
 370     return std::move(EC);
 371
 372   if (auto EC = DW.writeArray(Layout.StreamSizes))
 373     return std::move(EC);
 374
 375   for (const auto &Blocks : Layout.StreamMap) {
 376     if (auto EC = DW.writeArray(Blocks))
 377       return std::move(EC);
 378   }
 379
 380   return std::move(Buffer);
 381 }