[msf] Create LLVMDebugInfoMsf
This provides a better layering of responsibilities among different
aspects of PDB writing code. Some of the MSF related code was
contained in CodeView, and some was in PDB prior to this. Further,
we were often saying PDB when we meant MSF, and the two are
actually independent of each other since in theory you can have
other types of data besides PDB data in an MSF. So, this patch
separates the MSF specific code into its own library, with no
dependencies on anything else, and DebugInfoCodeView and
DebugInfoPDB take dependencies on DebugInfoMsf.
llvm-svn: 276458
diff --git a/llvm/lib/DebugInfo/Msf/MappedBlockStream.cpp b/llvm/lib/DebugInfo/Msf/MappedBlockStream.cpp
new file mode 100644
index 0000000..f2c8012
--- /dev/null
+++ b/llvm/lib/DebugInfo/Msf/MappedBlockStream.cpp
@@ -0,0 +1,311 @@
+//===- MappedBlockStream.cpp - Reads stream data from an MSF file ---------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/DebugInfo/Msf/MappedBlockStream.h"
+#include "llvm/DebugInfo/Msf/DirectoryStreamData.h"
+#include "llvm/DebugInfo/Msf/IMsfStreamData.h"
+#include "llvm/DebugInfo/Msf/IndexedStreamData.h"
+#include "llvm/DebugInfo/Msf/MsfError.h"
+
+using namespace llvm;
+using namespace llvm::msf;
+
+namespace {
+// This exists so that we can use make_unique (which requires a public default
+// constructor, while still keeping the constructor of MappedBlockStream
+// protected, forcing users to go through the `create` interface.
+class MappedBlockStreamImpl : public MappedBlockStream {
+public:
+ MappedBlockStreamImpl(std::unique_ptr<IMsfStreamData> Data,
+ const IMsfFile &File)
+ : MappedBlockStream(std::move(Data), File) {}
+};
+}
+
+typedef std::pair<uint32_t, uint32_t> Interval;
+static Interval intersect(const Interval &I1, const Interval &I2) {
+ return std::make_pair(std::max(I1.first, I2.first),
+ std::min(I1.second, I2.second));
+}
+
+MappedBlockStream::MappedBlockStream(std::unique_ptr<IMsfStreamData> Data,
+ const IMsfFile &File)
+ : Msf(File), Data(std::move(Data)) {}
+
+Error MappedBlockStream::readBytes(uint32_t Offset, uint32_t Size,
+ ArrayRef<uint8_t> &Buffer) const {
+ // Make sure we aren't trying to read beyond the end of the stream.
+ if (Size > Data->getLength())
+ return make_error<MsfError>(msf_error_code::insufficient_buffer);
+ if (Offset > Data->getLength() - Size)
+ return make_error<MsfError>(msf_error_code::insufficient_buffer);
+
+ if (tryReadContiguously(Offset, Size, Buffer))
+ return Error::success();
+
+ auto CacheIter = CacheMap.find(Offset);
+ if (CacheIter != CacheMap.end()) {
+ // Try to find an alloc that was large enough for this request.
+ for (auto &Entry : CacheIter->second) {
+ if (Entry.size() >= Size) {
+ Buffer = Entry.slice(0, Size);
+ return Error::success();
+ }
+ }
+ }
+
+ // We couldn't find a buffer that started at the correct offset (the most
+ // common scenario). Try to see if there is a buffer that starts at some
+ // other offset but overlaps the desired range.
+ for (auto &CacheItem : CacheMap) {
+ Interval RequestExtent = std::make_pair(Offset, Offset + Size);
+
+ // We already checked this one on the fast path above.
+ if (CacheItem.first == Offset)
+ continue;
+ // If the initial extent of the cached item is beyond the ending extent
+ // of the request, there is no overlap.
+ if (CacheItem.first >= Offset + Size)
+ continue;
+
+ // We really only have to check the last item in the list, since we append
+ // in order of increasing length.
+ if (CacheItem.second.empty())
+ continue;
+
+ auto CachedAlloc = CacheItem.second.back();
+ // If the initial extent of the request is beyond the ending extent of
+ // the cached item, there is no overlap.
+ Interval CachedExtent =
+ std::make_pair(CacheItem.first, CacheItem.first + CachedAlloc.size());
+ if (RequestExtent.first >= CachedExtent.first + CachedExtent.second)
+ continue;
+
+ Interval Intersection = intersect(CachedExtent, RequestExtent);
+ // Only use this if the entire request extent is contained in the cached
+ // extent.
+ if (Intersection != RequestExtent)
+ continue;
+
+ uint32_t CacheRangeOffset =
+ AbsoluteDifference(CachedExtent.first, Intersection.first);
+ Buffer = CachedAlloc.slice(CacheRangeOffset, Size);
+ return Error::success();
+ }
+
+ // Otherwise allocate a large enough buffer in the pool, memcpy the data
+ // into it, and return an ArrayRef to that. Do not touch existing pool
+ // allocations, as existing clients may be holding a pointer which must
+ // not be invalidated.
+ uint8_t *WriteBuffer = static_cast<uint8_t *>(Pool.Allocate(Size, 8));
+ if (auto EC = readBytes(Offset, MutableArrayRef<uint8_t>(WriteBuffer, Size)))
+ return EC;
+
+ if (CacheIter != CacheMap.end()) {
+ CacheIter->second.emplace_back(WriteBuffer, Size);
+ } else {
+ std::vector<CacheEntry> List;
+ List.emplace_back(WriteBuffer, Size);
+ CacheMap.insert(std::make_pair(Offset, List));
+ }
+ Buffer = ArrayRef<uint8_t>(WriteBuffer, Size);
+ return Error::success();
+}
+
+Error MappedBlockStream::readLongestContiguousChunk(
+ uint32_t Offset, ArrayRef<uint8_t> &Buffer) const {
+ // Make sure we aren't trying to read beyond the end of the stream.
+ if (Offset >= Data->getLength())
+ return make_error<MsfError>(msf_error_code::insufficient_buffer);
+ uint32_t First = Offset / Msf.getBlockSize();
+ uint32_t Last = First;
+
+ auto BlockList = Data->getStreamBlocks();
+ while (Last < Msf.getBlockCount() - 1) {
+ if (BlockList[Last] != BlockList[Last + 1] - 1)
+ break;
+ ++Last;
+ }
+
+ uint32_t OffsetInFirstBlock = Offset % Msf.getBlockSize();
+ uint32_t BytesFromFirstBlock = Msf.getBlockSize() - OffsetInFirstBlock;
+ uint32_t BlockSpan = Last - First + 1;
+ uint32_t ByteSpan =
+ BytesFromFirstBlock + (BlockSpan - 1) * Msf.getBlockSize();
+ auto Result = Msf.getBlockData(BlockList[First], Msf.getBlockSize());
+ if (!Result)
+ return Result.takeError();
+ Buffer = Result->drop_front(OffsetInFirstBlock);
+ Buffer = ArrayRef<uint8_t>(Buffer.data(), ByteSpan);
+ return Error::success();
+}
+
+uint32_t MappedBlockStream::getLength() const { return Data->getLength(); }
+
+Error MappedBlockStream::commit() const { return Error::success(); }
+
+bool MappedBlockStream::tryReadContiguously(uint32_t Offset, uint32_t Size,
+ ArrayRef<uint8_t> &Buffer) const {
+ // Attempt to fulfill the request with a reference directly into the stream.
+ // This can work even if the request crosses a block boundary, provided that
+ // all subsequent blocks are contiguous. For example, a 10k read with a 4k
+ // block size can be filled with a reference if, from the starting offset,
+ // 3 blocks in a row are contiguous.
+ uint32_t BlockNum = Offset / Msf.getBlockSize();
+ uint32_t OffsetInBlock = Offset % Msf.getBlockSize();
+ uint32_t BytesFromFirstBlock =
+ std::min(Size, Msf.getBlockSize() - OffsetInBlock);
+ uint32_t NumAdditionalBlocks =
+ llvm::alignTo(Size - BytesFromFirstBlock, Msf.getBlockSize()) /
+ Msf.getBlockSize();
+
+ auto BlockList = Data->getStreamBlocks();
+ uint32_t RequiredContiguousBlocks = NumAdditionalBlocks + 1;
+ uint32_t E = BlockList[BlockNum];
+ for (uint32_t I = 0; I < RequiredContiguousBlocks; ++I, ++E) {
+ if (BlockList[I + BlockNum] != E)
+ return false;
+ }
+
+ uint32_t FirstBlockAddr = BlockList[BlockNum];
+ auto Result = Msf.getBlockData(FirstBlockAddr, Msf.getBlockSize());
+ if (!Result) {
+ consumeError(Result.takeError());
+ return false;
+ }
+ auto Data = Result->drop_front(OffsetInBlock);
+ Buffer = ArrayRef<uint8_t>(Data.data(), Size);
+ return true;
+}
+
+Error MappedBlockStream::readBytes(uint32_t Offset,
+ MutableArrayRef<uint8_t> Buffer) const {
+ uint32_t BlockNum = Offset / Msf.getBlockSize();
+ uint32_t OffsetInBlock = Offset % Msf.getBlockSize();
+
+ // Make sure we aren't trying to read beyond the end of the stream.
+ if (Buffer.size() > Data->getLength())
+ return make_error<MsfError>(msf_error_code::insufficient_buffer);
+ if (Offset > Data->getLength() - Buffer.size())
+ return make_error<MsfError>(msf_error_code::insufficient_buffer);
+
+ uint32_t BytesLeft = Buffer.size();
+ uint32_t BytesWritten = 0;
+ uint8_t *WriteBuffer = Buffer.data();
+ auto BlockList = Data->getStreamBlocks();
+ while (BytesLeft > 0) {
+ uint32_t StreamBlockAddr = BlockList[BlockNum];
+
+ auto Result = Msf.getBlockData(StreamBlockAddr, Msf.getBlockSize());
+ if (!Result)
+ return Result.takeError();
+
+ auto Data = *Result;
+ const uint8_t *ChunkStart = Data.data() + OffsetInBlock;
+ uint32_t BytesInChunk =
+ std::min(BytesLeft, Msf.getBlockSize() - OffsetInBlock);
+ ::memcpy(WriteBuffer + BytesWritten, ChunkStart, BytesInChunk);
+
+ BytesWritten += BytesInChunk;
+ BytesLeft -= BytesInChunk;
+ ++BlockNum;
+ OffsetInBlock = 0;
+ }
+
+ return Error::success();
+}
+
+Error MappedBlockStream::writeBytes(uint32_t Offset,
+ ArrayRef<uint8_t> Buffer) const {
+ // Make sure we aren't trying to write beyond the end of the stream.
+ if (Buffer.size() > Data->getLength())
+ return make_error<MsfError>(msf_error_code::insufficient_buffer);
+
+ if (Offset > Data->getLength() - Buffer.size())
+ return make_error<MsfError>(msf_error_code::insufficient_buffer);
+
+ uint32_t BlockNum = Offset / Msf.getBlockSize();
+ uint32_t OffsetInBlock = Offset % Msf.getBlockSize();
+
+ uint32_t BytesLeft = Buffer.size();
+ auto BlockList = Data->getStreamBlocks();
+ uint32_t BytesWritten = 0;
+ while (BytesLeft > 0) {
+ uint32_t StreamBlockAddr = BlockList[BlockNum];
+ uint32_t BytesToWriteInChunk =
+ std::min(BytesLeft, Msf.getBlockSize() - OffsetInBlock);
+
+ const uint8_t *Chunk = Buffer.data() + BytesWritten;
+ ArrayRef<uint8_t> ChunkData(Chunk, BytesToWriteInChunk);
+ if (auto EC = Msf.setBlockData(StreamBlockAddr, OffsetInBlock, ChunkData))
+ return EC;
+
+ BytesLeft -= BytesToWriteInChunk;
+ BytesWritten += BytesToWriteInChunk;
+ ++BlockNum;
+ OffsetInBlock = 0;
+ }
+
+ // If this write overlapped a read which previously came from the pool,
+ // someone may still be holding a pointer to that alloc which is now invalid.
+ // Compute the overlapping range and update the cache entry, so any
+ // outstanding buffers are automatically updated.
+ for (const auto &MapEntry : CacheMap) {
+ // If the end of the written extent precedes the beginning of the cached
+ // extent, ignore this map entry.
+ if (Offset + BytesWritten < MapEntry.first)
+ continue;
+ for (const auto &Alloc : MapEntry.second) {
+ // If the end of the cached extent precedes the beginning of the written
+ // extent, ignore this alloc.
+ if (MapEntry.first + Alloc.size() < Offset)
+ continue;
+
+ // If we get here, they are guaranteed to overlap.
+ Interval WriteInterval = std::make_pair(Offset, Offset + BytesWritten);
+ Interval CachedInterval =
+ std::make_pair(MapEntry.first, MapEntry.first + Alloc.size());
+ // If they overlap, we need to write the new data into the overlapping
+ // range.
+ auto Intersection = intersect(WriteInterval, CachedInterval);
+ assert(Intersection.first <= Intersection.second);
+
+ uint32_t Length = Intersection.second - Intersection.first;
+ uint32_t SrcOffset =
+ AbsoluteDifference(WriteInterval.first, Intersection.first);
+ uint32_t DestOffset =
+ AbsoluteDifference(CachedInterval.first, Intersection.first);
+ ::memcpy(Alloc.data() + DestOffset, Buffer.data() + SrcOffset, Length);
+ }
+ }
+
+ return Error::success();
+}
+
+uint32_t MappedBlockStream::getNumBytesCopied() const {
+ return static_cast<uint32_t>(Pool.getBytesAllocated());
+}
+
+Expected<std::unique_ptr<MappedBlockStream>>
+MappedBlockStream::createIndexedStream(uint32_t StreamIdx,
+ const IMsfFile &File) {
+ if (StreamIdx >= File.getNumStreams())
+ return make_error<MsfError>(msf_error_code::no_stream);
+
+ auto Data = llvm::make_unique<IndexedStreamData>(StreamIdx, File);
+ return llvm::make_unique<MappedBlockStreamImpl>(std::move(Data), File);
+}
+
+Expected<std::unique_ptr<MappedBlockStream>>
+MappedBlockStream::createDirectoryStream(uint32_t Length,
+ ArrayRef<support::ulittle32_t> Blocks,
+ const IMsfFile &File) {
+ auto Data = llvm::make_unique<DirectoryStreamData>(Length, Blocks);
+ return llvm::make_unique<MappedBlockStreamImpl>(std::move(Data), File);
+}