llvm-6502/include/llvm/Support/StreamingMemoryObject.h
Alexander Kornienko cf0db29df2 Fixed/added namespace ending comments using clang-tidy. NFC
The patch is generated using this command:

tools/clang/tools/extra/clang-tidy/tool/run-clang-tidy.py -fix \
  -checks=-*,llvm-namespace-comment -header-filter='llvm/.*|clang/.*' \
  llvm/lib/


Thanks to Eugene Kosov for the original patch!



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@240137 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-19 15:57:42 +00:00

94 lines
3.7 KiB
C++

//===- StreamingMemoryObject.h - Streamable data interface -----*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_SUPPORT_STREAMINGMEMORYOBJECT_H
#define LLVM_SUPPORT_STREAMINGMEMORYOBJECT_H
#include "llvm/Support/Compiler.h"
#include "llvm/Support/DataStream.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/MemoryObject.h"
#include <memory>
#include <vector>
namespace llvm {
/// Interface to data which is actually streamed from a DataStreamer. In
/// addition to inherited members, it has the dropLeadingBytes and
/// setKnownObjectSize methods which are not applicable to non-streamed objects.
class StreamingMemoryObject : public MemoryObject {
public:
StreamingMemoryObject(std::unique_ptr<DataStreamer> Streamer);
uint64_t getExtent() const override;
uint64_t readBytes(uint8_t *Buf, uint64_t Size,
uint64_t Address) const override;
const uint8_t *getPointer(uint64_t address, uint64_t size) const override {
// FIXME: This could be fixed by ensuring the bytes are fetched and
// making a copy, requiring that the bitcode size be known, or
// otherwise ensuring that the memory doesn't go away/get reallocated,
// but it's not currently necessary. Users that need the pointer (any
// that need Blobs) don't stream.
report_fatal_error("getPointer in streaming memory objects not allowed");
return nullptr;
}
bool isValidAddress(uint64_t address) const override;
/// Drop s bytes from the front of the stream, pushing the positions of the
/// remaining bytes down by s. This is used to skip past the bitcode header,
/// since we don't know a priori if it's present, and we can't put bytes
/// back into the stream once we've read them.
bool dropLeadingBytes(size_t s);
/// If the data object size is known in advance, many of the operations can
/// be made more efficient, so this method should be called before reading
/// starts (although it can be called anytime).
void setKnownObjectSize(size_t size);
private:
const static uint32_t kChunkSize = 4096 * 4;
mutable std::vector<unsigned char> Bytes;
std::unique_ptr<DataStreamer> Streamer;
mutable size_t BytesRead; // Bytes read from stream
size_t BytesSkipped;// Bytes skipped at start of stream (e.g. wrapper/header)
mutable size_t ObjectSize; // 0 if unknown, set if wrapper seen or EOF reached
mutable bool EOFReached;
// Fetch enough bytes such that Pos can be read (i.e. BytesRead >
// Pos). Returns true if Pos can be read. Unlike most of the
// functions in BitcodeReader, returns true on success. Most of the
// requests will be small, but we fetch at kChunkSize bytes at a
// time to avoid making too many potentially expensive GetBytes
// calls.
bool fetchToPos(size_t Pos) const {
while (Pos >= BytesRead) {
if (EOFReached)
return false;
Bytes.resize(BytesRead + BytesSkipped + kChunkSize);
size_t bytes = Streamer->GetBytes(&Bytes[BytesRead + BytesSkipped],
kChunkSize);
BytesRead += bytes;
if (bytes == 0) { // reached EOF/ran out of bytes
if (ObjectSize == 0)
ObjectSize = BytesRead;
EOFReached = true;
}
}
return !ObjectSize || Pos < ObjectSize;
}
StreamingMemoryObject(const StreamingMemoryObject&) = delete;
void operator=(const StreamingMemoryObject&) = delete;
};
MemoryObject *getNonStreamedMemoryObject(
const unsigned char *Start, const unsigned char *End);
} // namespace llvm
#endif // STREAMINGMEMORYOBJECT_H_