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//==- MappedBlockStream.h - Discontiguous stream data in an MSF --*- 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_MSF_MAPPEDBLOCKSTREAM_H
#define LLVM_DEBUGINFO_MSF_MAPPEDBLOCKSTREAM_H
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/DebugInfo/MSF/MSFCommon.h"
#include "llvm/Support/Allocator.h"
#include "llvm/Support/BinaryStream.h"
#include "llvm/Support/BinaryStreamRef.h"
#include "llvm/Support/Endian.h"
#include "llvm/Support/Error.h"
#include <cstdint>
#include <memory>
#include <vector>
namespace llvm {
namespace msf {
/// MappedBlockStream represents data stored in an MSF file into chunks of a
/// particular size (called the Block Size), and whose chunks may not be
/// necessarily contiguous. The arrangement of these chunks MSF the file
/// is described by some other metadata contained within the MSF file. In
/// the case of a standard MSF Stream, the layout of the stream's blocks
/// is described by the MSF "directory", but in the case of the directory
/// itself, the layout is described by an array at a fixed location within
/// the MSF. MappedBlockStream provides methods for reading from and writing
/// to one of these streams transparently, as if it were a contiguous sequence
/// of bytes.
class MappedBlockStream : public BinaryStream {
friend class WritableMappedBlockStream;
public:
static std::unique_ptr<MappedBlockStream>
createStream(uint32_t BlockSize, const MSFStreamLayout &Layout,
BinaryStreamRef MsfData, BumpPtrAllocator &Allocator);
static std::unique_ptr<MappedBlockStream>
createIndexedStream(const MSFLayout &Layout, BinaryStreamRef MsfData,
uint32_t StreamIndex, BumpPtrAllocator &Allocator);
static std::unique_ptr<MappedBlockStream>
createFpmStream(const MSFLayout &Layout, BinaryStreamRef MsfData,
BumpPtrAllocator &Allocator);
static std::unique_ptr<MappedBlockStream>
createDirectoryStream(const MSFLayout &Layout, BinaryStreamRef MsfData,
BumpPtrAllocator &Allocator);
llvm::endianness getEndian() const override {
return llvm::endianness::little;
}
Error readBytes(uint64_t Offset, uint64_t Size,
ArrayRef<uint8_t> &Buffer) override;
Error readLongestContiguousChunk(uint64_t Offset,
ArrayRef<uint8_t> &Buffer) override;
uint64_t getLength() override;
BumpPtrAllocator &getAllocator() { return Allocator; }
void invalidateCache();
uint32_t getBlockSize() const { return BlockSize; }
uint32_t getNumBlocks() const { return StreamLayout.Blocks.size(); }
uint32_t getStreamLength() const { return StreamLayout.Length; }
protected:
MappedBlockStream(uint32_t BlockSize, const MSFStreamLayout &StreamLayout,
BinaryStreamRef MsfData, BumpPtrAllocator &Allocator);
private:
const MSFStreamLayout &getStreamLayout() const { return StreamLayout; }
void fixCacheAfterWrite(uint64_t Offset, ArrayRef<uint8_t> Data) const;
Error readBytes(uint64_t Offset, MutableArrayRef<uint8_t> Buffer);
bool tryReadContiguously(uint64_t Offset, uint64_t Size,
ArrayRef<uint8_t> &Buffer);
const uint32_t BlockSize;
const MSFStreamLayout StreamLayout;
BinaryStreamRef MsfData;
using CacheEntry = MutableArrayRef<uint8_t>;
// We just store the allocator by reference. We use this to allocate
// contiguous memory for things like arrays or strings that cross a block
// boundary, and this memory is expected to outlive the stream. For example,
// someone could create a stream, read some stuff, then close the stream, and
// we would like outstanding references to fields to remain valid since the
// entire file is mapped anyway. Because of that, the user must supply the
// allocator to allocate broken records from.
BumpPtrAllocator &Allocator;
DenseMap<uint32_t, std::vector<CacheEntry>> CacheMap;
};
class WritableMappedBlockStream : public WritableBinaryStream {
public:
static std::unique_ptr<WritableMappedBlockStream>
createStream(uint32_t BlockSize, const MSFStreamLayout &Layout,
WritableBinaryStreamRef MsfData, BumpPtrAllocator &Allocator);
static std::unique_ptr<WritableMappedBlockStream>
createIndexedStream(const MSFLayout &Layout, WritableBinaryStreamRef MsfData,
uint32_t StreamIndex, BumpPtrAllocator &Allocator);
static std::unique_ptr<WritableMappedBlockStream>
createDirectoryStream(const MSFLayout &Layout,
WritableBinaryStreamRef MsfData,
BumpPtrAllocator &Allocator);
static std::unique_ptr<WritableMappedBlockStream>
createFpmStream(const MSFLayout &Layout, WritableBinaryStreamRef MsfData,
BumpPtrAllocator &Allocator, bool AltFpm = false);
llvm::endianness getEndian() const override {
return llvm::endianness::little;
}
Error readBytes(uint64_t Offset, uint64_t Size,
ArrayRef<uint8_t> &Buffer) override;
Error readLongestContiguousChunk(uint64_t Offset,
ArrayRef<uint8_t> &Buffer) override;
uint64_t getLength() override;
Error writeBytes(uint64_t Offset, ArrayRef<uint8_t> Buffer) override;
Error commit() override;
const MSFStreamLayout &getStreamLayout() const {
return ReadInterface.getStreamLayout();
}
uint32_t getBlockSize() const { return ReadInterface.getBlockSize(); }
uint32_t getNumBlocks() const { return ReadInterface.getNumBlocks(); }
uint32_t getStreamLength() const { return ReadInterface.getStreamLength(); }
protected:
WritableMappedBlockStream(uint32_t BlockSize,
const MSFStreamLayout &StreamLayout,
WritableBinaryStreamRef MsfData,
BumpPtrAllocator &Allocator);
private:
MappedBlockStream ReadInterface;
WritableBinaryStreamRef WriteInterface;
};
} // namespace msf
} // end namespace llvm
#endif // LLVM_DEBUGINFO_MSF_MAPPEDBLOCKSTREAM_H
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