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//===-- Decompressor.cpp --------------------------------------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
#include "llvm/Object/Decompressor.h"
#include "llvm/BinaryFormat/ELF.h"
#include "llvm/Object/ObjectFile.h"
#include "llvm/Support/Compression.h"
#include "llvm/Support/DataExtractor.h"
#include "llvm/Support/Endian.h"
using namespace llvm;
using namespace llvm::support::endian;
using namespace object;
Expected<Decompressor> Decompressor::create(StringRef Name, StringRef Data,
bool IsLE, bool Is64Bit) {
Decompressor D(Data);
if (Error Err = D.consumeCompressedHeader(Is64Bit, IsLE))
return std::move(Err);
return D;
}
Decompressor::Decompressor(StringRef Data)
: SectionData(Data), DecompressedSize(0) {}
Error Decompressor::consumeCompressedHeader(bool Is64Bit, bool IsLittleEndian) {
using namespace ELF;
uint64_t HdrSize = Is64Bit ? sizeof(Elf64_Chdr) : sizeof(Elf32_Chdr);
if (SectionData.size() < HdrSize)
return createError("corrupted compressed section header");
DataExtractor Extractor(SectionData, IsLittleEndian, 0);
uint64_t Offset = 0;
auto ChType = Extractor.getUnsigned(&Offset, Is64Bit ? sizeof(Elf64_Word)
: sizeof(Elf32_Word));
switch (ChType) {
case ELFCOMPRESS_ZLIB:
CompressionType = DebugCompressionType::Zlib;
break;
case ELFCOMPRESS_ZSTD:
CompressionType = DebugCompressionType::Zstd;
break;
default:
return createError("unsupported compression type (" + Twine(ChType) + ")");
}
if (const char *Reason = llvm::compression::getReasonIfUnsupported(
compression::formatFor(CompressionType)))
return createError(Reason);
// Skip Elf64_Chdr::ch_reserved field.
if (Is64Bit)
Offset += sizeof(Elf64_Word);
DecompressedSize = Extractor.getUnsigned(
&Offset, Is64Bit ? sizeof(Elf64_Xword) : sizeof(Elf32_Word));
SectionData = SectionData.substr(HdrSize);
return Error::success();
}
Error Decompressor::decompress(MutableArrayRef<uint8_t> Output) {
return compression::decompress(CompressionType,
arrayRefFromStringRef(SectionData),
Output.data(), Output.size());
}
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