1 //===- MappedBlockStream.cpp - Reads stream data from an MSF file ---------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 #include "llvm/DebugInfo/MSF/MappedBlockStream.h"
12 #include "llvm/DebugInfo/MSF/IMSFFile.h"
13 #include "llvm/DebugInfo/MSF/MSFCommon.h"
14 #include "llvm/DebugInfo/MSF/MSFStreamLayout.h"
15 #include "llvm/Support/BinaryStreamError.h"
18 using namespace llvm::msf;
21 template <typename Base> class MappedBlockStreamImpl : public Base {
23 template <typename... Args>
24 MappedBlockStreamImpl(Args &&... Params)
25 : Base(std::forward<Args>(Params)...) {}
29 static void initializeFpmStreamLayout(const MSFLayout &Layout,
30 MSFStreamLayout &FpmLayout) {
31 uint32_t NumFpmIntervals = msf::getNumFpmIntervals(Layout);
32 support::ulittle32_t FpmBlock = Layout.SB->FreeBlockMapBlock;
33 assert(FpmBlock == 1 || FpmBlock == 2);
34 while (NumFpmIntervals > 0) {
35 FpmLayout.Blocks.push_back(FpmBlock);
36 FpmBlock += msf::getFpmIntervalLength(Layout);
39 FpmLayout.Length = msf::getFullFpmByteSize(Layout);
42 typedef std::pair<uint32_t, uint32_t> Interval;
43 static Interval intersect(const Interval &I1, const Interval &I2) {
44 return std::make_pair(std::max(I1.first, I2.first),
45 std::min(I1.second, I2.second));
48 MappedBlockStream::MappedBlockStream(uint32_t BlockSize, uint32_t NumBlocks,
49 const MSFStreamLayout &Layout,
50 BinaryStreamRef MsfData)
51 : BlockSize(BlockSize), NumBlocks(NumBlocks), StreamLayout(Layout),
54 std::unique_ptr<MappedBlockStream>
55 MappedBlockStream::createStream(uint32_t BlockSize, uint32_t NumBlocks,
56 const MSFStreamLayout &Layout,
57 BinaryStreamRef MsfData) {
58 return llvm::make_unique<MappedBlockStreamImpl<MappedBlockStream>>(
59 BlockSize, NumBlocks, Layout, MsfData);
62 std::unique_ptr<MappedBlockStream> MappedBlockStream::createIndexedStream(
63 const MSFLayout &Layout, BinaryStreamRef MsfData, uint32_t StreamIndex) {
64 assert(StreamIndex < Layout.StreamMap.size() && "Invalid stream index");
66 SL.Blocks = Layout.StreamMap[StreamIndex];
67 SL.Length = Layout.StreamSizes[StreamIndex];
68 return llvm::make_unique<MappedBlockStreamImpl<MappedBlockStream>>(
69 Layout.SB->BlockSize, Layout.SB->NumBlocks, SL, MsfData);
72 std::unique_ptr<MappedBlockStream>
73 MappedBlockStream::createDirectoryStream(const MSFLayout &Layout,
74 BinaryStreamRef MsfData) {
76 SL.Blocks = Layout.DirectoryBlocks;
77 SL.Length = Layout.SB->NumDirectoryBytes;
78 return createStream(Layout.SB->BlockSize, Layout.SB->NumBlocks, SL, MsfData);
81 std::unique_ptr<MappedBlockStream>
82 MappedBlockStream::createFpmStream(const MSFLayout &Layout,
83 BinaryStreamRef MsfData) {
85 initializeFpmStreamLayout(Layout, SL);
86 return createStream(Layout.SB->BlockSize, Layout.SB->NumBlocks, SL, MsfData);
89 Error MappedBlockStream::readBytes(uint32_t Offset, uint32_t Size,
90 ArrayRef<uint8_t> &Buffer) {
91 // Make sure we aren't trying to read beyond the end of the stream.
92 if (auto EC = checkOffset(Offset, Size))
95 if (tryReadContiguously(Offset, Size, Buffer))
96 return Error::success();
98 auto CacheIter = CacheMap.find(Offset);
99 if (CacheIter != CacheMap.end()) {
100 // Try to find an alloc that was large enough for this request.
101 for (auto &Entry : CacheIter->second) {
102 if (Entry.size() >= Size) {
103 Buffer = Entry.slice(0, Size);
104 return Error::success();
109 // We couldn't find a buffer that started at the correct offset (the most
110 // common scenario). Try to see if there is a buffer that starts at some
111 // other offset but overlaps the desired range.
112 for (auto &CacheItem : CacheMap) {
113 Interval RequestExtent = std::make_pair(Offset, Offset + Size);
115 // We already checked this one on the fast path above.
116 if (CacheItem.first == Offset)
118 // If the initial extent of the cached item is beyond the ending extent
119 // of the request, there is no overlap.
120 if (CacheItem.first >= Offset + Size)
123 // We really only have to check the last item in the list, since we append
124 // in order of increasing length.
125 if (CacheItem.second.empty())
128 auto CachedAlloc = CacheItem.second.back();
129 // If the initial extent of the request is beyond the ending extent of
130 // the cached item, there is no overlap.
131 Interval CachedExtent =
132 std::make_pair(CacheItem.first, CacheItem.first + CachedAlloc.size());
133 if (RequestExtent.first >= CachedExtent.first + CachedExtent.second)
136 Interval Intersection = intersect(CachedExtent, RequestExtent);
137 // Only use this if the entire request extent is contained in the cached
139 if (Intersection != RequestExtent)
142 uint32_t CacheRangeOffset =
143 AbsoluteDifference(CachedExtent.first, Intersection.first);
144 Buffer = CachedAlloc.slice(CacheRangeOffset, Size);
145 return Error::success();
148 // Otherwise allocate a large enough buffer in the pool, memcpy the data
149 // into it, and return an ArrayRef to that. Do not touch existing pool
150 // allocations, as existing clients may be holding a pointer which must
151 // not be invalidated.
152 uint8_t *WriteBuffer = static_cast<uint8_t *>(Pool.Allocate(Size, 8));
153 if (auto EC = readBytes(Offset, MutableArrayRef<uint8_t>(WriteBuffer, Size)))
156 if (CacheIter != CacheMap.end()) {
157 CacheIter->second.emplace_back(WriteBuffer, Size);
159 std::vector<CacheEntry> List;
160 List.emplace_back(WriteBuffer, Size);
161 CacheMap.insert(std::make_pair(Offset, List));
163 Buffer = ArrayRef<uint8_t>(WriteBuffer, Size);
164 return Error::success();
167 Error MappedBlockStream::readLongestContiguousChunk(uint32_t Offset,
168 ArrayRef<uint8_t> &Buffer) {
169 // Make sure we aren't trying to read beyond the end of the stream.
170 if (auto EC = checkOffset(Offset, 1))
173 uint32_t First = Offset / BlockSize;
174 uint32_t Last = First;
176 while (Last < NumBlocks - 1) {
177 if (StreamLayout.Blocks[Last] != StreamLayout.Blocks[Last + 1] - 1)
182 uint32_t OffsetInFirstBlock = Offset % BlockSize;
183 uint32_t BytesFromFirstBlock = BlockSize - OffsetInFirstBlock;
184 uint32_t BlockSpan = Last - First + 1;
185 uint32_t ByteSpan = BytesFromFirstBlock + (BlockSpan - 1) * BlockSize;
187 ArrayRef<uint8_t> BlockData;
188 uint32_t MsfOffset = blockToOffset(StreamLayout.Blocks[First], BlockSize);
189 if (auto EC = MsfData.readBytes(MsfOffset, BlockSize, BlockData))
192 BlockData = BlockData.drop_front(OffsetInFirstBlock);
193 Buffer = ArrayRef<uint8_t>(BlockData.data(), ByteSpan);
194 return Error::success();
197 uint32_t MappedBlockStream::getLength() { return StreamLayout.Length; }
199 bool MappedBlockStream::tryReadContiguously(uint32_t Offset, uint32_t Size,
200 ArrayRef<uint8_t> &Buffer) {
202 Buffer = ArrayRef<uint8_t>();
205 // Attempt to fulfill the request with a reference directly into the stream.
206 // This can work even if the request crosses a block boundary, provided that
207 // all subsequent blocks are contiguous. For example, a 10k read with a 4k
208 // block size can be filled with a reference if, from the starting offset,
209 // 3 blocks in a row are contiguous.
210 uint32_t BlockNum = Offset / BlockSize;
211 uint32_t OffsetInBlock = Offset % BlockSize;
212 uint32_t BytesFromFirstBlock = std::min(Size, BlockSize - OffsetInBlock);
213 uint32_t NumAdditionalBlocks =
214 llvm::alignTo(Size - BytesFromFirstBlock, BlockSize) / BlockSize;
216 uint32_t RequiredContiguousBlocks = NumAdditionalBlocks + 1;
217 uint32_t E = StreamLayout.Blocks[BlockNum];
218 for (uint32_t I = 0; I < RequiredContiguousBlocks; ++I, ++E) {
219 if (StreamLayout.Blocks[I + BlockNum] != E)
223 // Read out the entire block where the requested offset starts. Then drop
224 // bytes from the beginning so that the actual starting byte lines up with
225 // the requested starting byte. Then, since we know this is a contiguous
226 // cross-block span, explicitly resize the ArrayRef to cover the entire
228 ArrayRef<uint8_t> BlockData;
229 uint32_t FirstBlockAddr = StreamLayout.Blocks[BlockNum];
230 uint32_t MsfOffset = blockToOffset(FirstBlockAddr, BlockSize);
231 if (auto EC = MsfData.readBytes(MsfOffset, BlockSize, BlockData)) {
232 consumeError(std::move(EC));
235 BlockData = BlockData.drop_front(OffsetInBlock);
236 Buffer = ArrayRef<uint8_t>(BlockData.data(), Size);
240 Error MappedBlockStream::readBytes(uint32_t Offset,
241 MutableArrayRef<uint8_t> Buffer) {
242 uint32_t BlockNum = Offset / BlockSize;
243 uint32_t OffsetInBlock = Offset % BlockSize;
245 // Make sure we aren't trying to read beyond the end of the stream.
246 if (auto EC = checkOffset(Offset, Buffer.size()))
249 uint32_t BytesLeft = Buffer.size();
250 uint32_t BytesWritten = 0;
251 uint8_t *WriteBuffer = Buffer.data();
252 while (BytesLeft > 0) {
253 uint32_t StreamBlockAddr = StreamLayout.Blocks[BlockNum];
255 ArrayRef<uint8_t> BlockData;
256 uint32_t Offset = blockToOffset(StreamBlockAddr, BlockSize);
257 if (auto EC = MsfData.readBytes(Offset, BlockSize, BlockData))
260 const uint8_t *ChunkStart = BlockData.data() + OffsetInBlock;
261 uint32_t BytesInChunk = std::min(BytesLeft, BlockSize - OffsetInBlock);
262 ::memcpy(WriteBuffer + BytesWritten, ChunkStart, BytesInChunk);
264 BytesWritten += BytesInChunk;
265 BytesLeft -= BytesInChunk;
270 return Error::success();
273 uint32_t MappedBlockStream::getNumBytesCopied() const {
274 return static_cast<uint32_t>(Pool.getBytesAllocated());
277 void MappedBlockStream::invalidateCache() { CacheMap.shrink_and_clear(); }
279 void MappedBlockStream::fixCacheAfterWrite(uint32_t Offset,
280 ArrayRef<uint8_t> Data) const {
281 // If this write overlapped a read which previously came from the pool,
282 // someone may still be holding a pointer to that alloc which is now invalid.
283 // Compute the overlapping range and update the cache entry, so any
284 // outstanding buffers are automatically updated.
285 for (const auto &MapEntry : CacheMap) {
286 // If the end of the written extent precedes the beginning of the cached
287 // extent, ignore this map entry.
288 if (Offset + Data.size() < MapEntry.first)
290 for (const auto &Alloc : MapEntry.second) {
291 // If the end of the cached extent precedes the beginning of the written
292 // extent, ignore this alloc.
293 if (MapEntry.first + Alloc.size() < Offset)
296 // If we get here, they are guaranteed to overlap.
297 Interval WriteInterval = std::make_pair(Offset, Offset + Data.size());
298 Interval CachedInterval =
299 std::make_pair(MapEntry.first, MapEntry.first + Alloc.size());
300 // If they overlap, we need to write the new data into the overlapping
302 auto Intersection = intersect(WriteInterval, CachedInterval);
303 assert(Intersection.first <= Intersection.second);
305 uint32_t Length = Intersection.second - Intersection.first;
307 AbsoluteDifference(WriteInterval.first, Intersection.first);
308 uint32_t DestOffset =
309 AbsoluteDifference(CachedInterval.first, Intersection.first);
310 ::memcpy(Alloc.data() + DestOffset, Data.data() + SrcOffset, Length);
315 WritableMappedBlockStream::WritableMappedBlockStream(
316 uint32_t BlockSize, uint32_t NumBlocks, const MSFStreamLayout &Layout,
317 WritableBinaryStreamRef MsfData)
318 : ReadInterface(BlockSize, NumBlocks, Layout, MsfData),
319 WriteInterface(MsfData) {}
321 std::unique_ptr<WritableMappedBlockStream>
322 WritableMappedBlockStream::createStream(uint32_t BlockSize, uint32_t NumBlocks,
323 const MSFStreamLayout &Layout,
324 WritableBinaryStreamRef MsfData) {
325 return llvm::make_unique<MappedBlockStreamImpl<WritableMappedBlockStream>>(
326 BlockSize, NumBlocks, Layout, MsfData);
329 std::unique_ptr<WritableMappedBlockStream>
330 WritableMappedBlockStream::createIndexedStream(const MSFLayout &Layout,
331 WritableBinaryStreamRef MsfData,
332 uint32_t StreamIndex) {
333 assert(StreamIndex < Layout.StreamMap.size() && "Invalid stream index");
335 SL.Blocks = Layout.StreamMap[StreamIndex];
336 SL.Length = Layout.StreamSizes[StreamIndex];
337 return createStream(Layout.SB->BlockSize, Layout.SB->NumBlocks, SL, MsfData);
340 std::unique_ptr<WritableMappedBlockStream>
341 WritableMappedBlockStream::createDirectoryStream(
342 const MSFLayout &Layout, WritableBinaryStreamRef MsfData) {
344 SL.Blocks = Layout.DirectoryBlocks;
345 SL.Length = Layout.SB->NumDirectoryBytes;
346 return createStream(Layout.SB->BlockSize, Layout.SB->NumBlocks, SL, MsfData);
349 std::unique_ptr<WritableMappedBlockStream>
350 WritableMappedBlockStream::createFpmStream(const MSFLayout &Layout,
351 WritableBinaryStreamRef MsfData) {
353 initializeFpmStreamLayout(Layout, SL);
354 return createStream(Layout.SB->BlockSize, Layout.SB->NumBlocks, SL, MsfData);
357 Error WritableMappedBlockStream::readBytes(uint32_t Offset, uint32_t Size,
358 ArrayRef<uint8_t> &Buffer) {
359 return ReadInterface.readBytes(Offset, Size, Buffer);
362 Error WritableMappedBlockStream::readLongestContiguousChunk(
363 uint32_t Offset, ArrayRef<uint8_t> &Buffer) {
364 return ReadInterface.readLongestContiguousChunk(Offset, Buffer);
367 uint32_t WritableMappedBlockStream::getLength() {
368 return ReadInterface.getLength();
371 Error WritableMappedBlockStream::writeBytes(uint32_t Offset,
372 ArrayRef<uint8_t> Buffer) {
373 // Make sure we aren't trying to write beyond the end of the stream.
374 if (auto EC = checkOffset(Offset, Buffer.size()))
377 uint32_t BlockNum = Offset / getBlockSize();
378 uint32_t OffsetInBlock = Offset % getBlockSize();
380 uint32_t BytesLeft = Buffer.size();
381 uint32_t BytesWritten = 0;
382 while (BytesLeft > 0) {
383 uint32_t StreamBlockAddr = getStreamLayout().Blocks[BlockNum];
384 uint32_t BytesToWriteInChunk =
385 std::min(BytesLeft, getBlockSize() - OffsetInBlock);
387 const uint8_t *Chunk = Buffer.data() + BytesWritten;
388 ArrayRef<uint8_t> ChunkData(Chunk, BytesToWriteInChunk);
389 uint32_t MsfOffset = blockToOffset(StreamBlockAddr, getBlockSize());
390 MsfOffset += OffsetInBlock;
391 if (auto EC = WriteInterface.writeBytes(MsfOffset, ChunkData))
394 BytesLeft -= BytesToWriteInChunk;
395 BytesWritten += BytesToWriteInChunk;
400 ReadInterface.fixCacheAfterWrite(Offset, Buffer);
402 return Error::success();
405 Error WritableMappedBlockStream::commit() { return WriteInterface.commit(); }