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
113 lines
4.2 KiB
C++
113 lines
4.2 KiB
C++
//===- WasmObjcopy.cpp ----------------------------------------------------===//
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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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#include "WasmObjcopy.h"
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#include "CopyConfig.h"
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#include "Object.h"
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#include "Reader.h"
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#include "Writer.h"
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#include "llvm/Support/Errc.h"
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#include "llvm/Support/FileOutputBuffer.h"
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namespace llvm {
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namespace objcopy {
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namespace wasm {
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using namespace object;
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static Error dumpSectionToFile(StringRef SecName, StringRef Filename,
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Object &Obj) {
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for (const Section &Sec : Obj.Sections) {
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if (Sec.Name == SecName) {
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ArrayRef<uint8_t> Contents = Sec.Contents;
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Expected<std::unique_ptr<FileOutputBuffer>> BufferOrErr =
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FileOutputBuffer::create(Filename, Contents.size());
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if (!BufferOrErr)
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return BufferOrErr.takeError();
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std::unique_ptr<FileOutputBuffer> Buf = std::move(*BufferOrErr);
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std::copy(Contents.begin(), Contents.end(), Buf->getBufferStart());
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if (Error E = Buf->commit())
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return E;
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return Error::success();
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}
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}
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return createStringError(errc::invalid_argument, "section '%s' not found",
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SecName.str().c_str());
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}
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static Error handleArgs(const CopyConfig &Config, Object &Obj) {
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// Only support AddSection, DumpSection, RemoveSection for now.
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for (StringRef Flag : Config.DumpSection) {
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StringRef SecName;
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StringRef FileName;
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std::tie(SecName, FileName) = Flag.split("=");
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if (Error E = dumpSectionToFile(SecName, FileName, Obj))
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return createFileError(FileName, std::move(E));
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}
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Obj.removeSections([&Config](const Section &Sec) {
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if (Config.ToRemove.matches(Sec.Name))
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return true;
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return false;
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});
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for (StringRef Flag : Config.AddSection) {
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StringRef SecName, FileName;
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std::tie(SecName, FileName) = Flag.split("=");
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ErrorOr<std::unique_ptr<MemoryBuffer>> BufOrErr =
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MemoryBuffer::getFile(FileName);
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if (!BufOrErr)
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return createFileError(FileName, errorCodeToError(BufOrErr.getError()));
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Section Sec;
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Sec.SectionType = llvm::wasm::WASM_SEC_CUSTOM;
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Sec.Name = SecName;
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std::unique_ptr<MemoryBuffer> Buf = std::move(*BufOrErr);
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Sec.Contents = makeArrayRef<uint8_t>(
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reinterpret_cast<const uint8_t *>(Buf->getBufferStart()),
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Buf->getBufferSize());
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Obj.addSectionWithOwnedContents(Sec, std::move(Buf));
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}
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if (!Config.AddGnuDebugLink.empty() || Config.ExtractPartition ||
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!Config.SplitDWO.empty() || !Config.SymbolsPrefix.empty() ||
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!Config.AllocSectionsPrefix.empty() ||
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Config.DiscardMode != DiscardType::None || Config.NewSymbolVisibility ||
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!Config.SymbolsToAdd.empty() || !Config.RPathToAdd.empty() ||
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!Config.OnlySection.empty() || !Config.SymbolsToGlobalize.empty() ||
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!Config.SymbolsToKeep.empty() || !Config.SymbolsToLocalize.empty() ||
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!Config.SymbolsToRemove.empty() ||
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!Config.UnneededSymbolsToRemove.empty() ||
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!Config.SymbolsToWeaken.empty() || !Config.SymbolsToKeepGlobal.empty() ||
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!Config.SectionsToRename.empty() || !Config.SetSectionAlignment.empty() ||
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!Config.SetSectionFlags.empty() || !Config.SymbolsToRename.empty()) {
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return createStringError(
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llvm::errc::invalid_argument,
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"only add-section, dump-section, and remove-section are supported");
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}
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return Error::success();
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}
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Error executeObjcopyOnBinary(const CopyConfig &Config,
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object::WasmObjectFile &In, raw_ostream &Out) {
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Reader TheReader(In);
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Expected<std::unique_ptr<Object>> ObjOrErr = TheReader.create();
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if (!ObjOrErr)
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return createFileError(Config.InputFilename, ObjOrErr.takeError());
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Object *Obj = ObjOrErr->get();
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assert(Obj && "Unable to deserialize Wasm object");
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if (Error E = handleArgs(Config, *Obj))
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return E;
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Writer TheWriter(*Obj, Out);
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if (Error E = TheWriter.write())
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return createFileError(Config.OutputFilename, std::move(E));
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return Error::success();
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}
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} // end namespace wasm
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} // end namespace objcopy
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} // end namespace llvm
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