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4f16e177e1
During D88827 it was requested to remove the local implementation
of Memory/File Buffers:
// TODO: refactor the buffer classes in LLVM to enable us to use them here
// directly.
This patch uses raw_ostream instead of Buffers. Generally, using streams
could allow us to reduce memory usages. No need to load all data into the
memory - the data could be streamed through a smaller buffer.
Thus, this patch uses raw_ostream as an interface for output data:
Error executeObjcopyOnBinary(CopyConfig &Config,
object::Binary &In,
raw_ostream &Out);
Note 1. This patch does not change the implementation of Writers
so that data would be directly stored into raw_ostream.
This is assumed to be done later.
Note 2. It would be better if Writers would be implemented in a such way
that data could be streamed without seeking/updating. If that would be
inconvenient then raw_ostream could be replaced with raw_pwrite_stream
to have a possibility to seek back and update file headers.
This is assumed to be done later if necessary.
Note 3. Current FileOutputBuffer allows using a memory-mapped file.
The raw_fd_ostream (which could be used if data should be stored in the file)
does not allow us to use a memory-mapped file. Memory map functionality
could be implemented for raw_fd_ostream:
It is possible to add resize() method into raw_ostream.
class raw_ostream {
void resize(uint64_t size);
}
That method, implemented for raw_fd_ostream, could create a memory-mapped file.
The streamed data would be written into that memory file then.
Thus we would be able to use memory-mapped files with raw_fd_ostream.
This is assumed to be done later if necessary.
Differential Revision: https://reviews.llvm.org/D91028
46 lines
1.5 KiB
C++
46 lines
1.5 KiB
C++
//===- llvm-objcopy.h -------------------------------------------*- C++ -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_TOOLS_OBJCOPY_OBJCOPY_H
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#define LLVM_TOOLS_OBJCOPY_OBJCOPY_H
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#include "llvm/Support/Error.h"
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#include "llvm/Support/raw_ostream.h"
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namespace llvm {
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struct NewArchiveMember;
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namespace object {
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class Archive;
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} // end namespace object
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namespace objcopy {
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struct CopyConfig;
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Expected<std::vector<NewArchiveMember>>
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createNewArchiveMembers(CopyConfig &Config, const object::Archive &Ar);
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/// A writeToFile helper creates an output stream, based on the specified
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/// \p OutputFileName: std::outs for the "-", raw_null_ostream for
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/// the "/dev/null", temporary file in the same directory as the final output
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/// file for other names. The final output file is atomically replaced with
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/// the temporary file after \p Write handler is finished. \p KeepOwnership
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/// used to setting specified \p UserID and \p GroupID for the resulting file
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/// if writeToFile is called under /root.
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Error writeToFile(StringRef OutputFileName,
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std::function<Error(raw_ostream &)> Write,
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bool KeepOwnership = false, unsigned UserID = 0,
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unsigned GroupID = 0);
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} // end namespace objcopy
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} // end namespace llvm
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#endif // LLVM_TOOLS_OBJCOPY_OBJCOPY_H
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