71 lines · cpp
1//===-- Decompressor.cpp --------------------------------------------------===//2//3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.4// See https://llvm.org/LICENSE.txt for license information.5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception6//7//===----------------------------------------------------------------------===//8 9#include "llvm/Object/Decompressor.h"10#include "llvm/ADT/StringExtras.h"11#include "llvm/BinaryFormat/ELF.h"12#include "llvm/Object/ObjectFile.h"13#include "llvm/Support/Compression.h"14#include "llvm/Support/DataExtractor.h"15#include "llvm/Support/Endian.h"16 17using namespace llvm;18using namespace llvm::support::endian;19using namespace object;20 21Expected<Decompressor> Decompressor::create(StringRef Name, StringRef Data,22 bool IsLE, bool Is64Bit) {23 Decompressor D(Data);24 if (Error Err = D.consumeCompressedHeader(Is64Bit, IsLE))25 return std::move(Err);26 return D;27}28 29Decompressor::Decompressor(StringRef Data)30 : SectionData(Data), DecompressedSize(0) {}31 32Error Decompressor::consumeCompressedHeader(bool Is64Bit, bool IsLittleEndian) {33 using namespace ELF;34 uint64_t HdrSize = Is64Bit ? sizeof(Elf64_Chdr) : sizeof(Elf32_Chdr);35 if (SectionData.size() < HdrSize)36 return createError("corrupted compressed section header");37 38 DataExtractor Extractor(SectionData, IsLittleEndian, 0);39 uint64_t Offset = 0;40 auto ChType = Extractor.getUnsigned(&Offset, Is64Bit ? sizeof(Elf64_Word)41 : sizeof(Elf32_Word));42 switch (ChType) {43 case ELFCOMPRESS_ZLIB:44 CompressionType = DebugCompressionType::Zlib;45 break;46 case ELFCOMPRESS_ZSTD:47 CompressionType = DebugCompressionType::Zstd;48 break;49 default:50 return createError("unsupported compression type (" + Twine(ChType) + ")");51 }52 if (const char *Reason = llvm::compression::getReasonIfUnsupported(53 compression::formatFor(CompressionType)))54 return createError(Reason);55 56 // Skip Elf64_Chdr::ch_reserved field.57 if (Is64Bit)58 Offset += sizeof(Elf64_Word);59 60 DecompressedSize = Extractor.getUnsigned(61 &Offset, Is64Bit ? sizeof(Elf64_Xword) : sizeof(Elf32_Word));62 SectionData = SectionData.substr(HdrSize);63 return Error::success();64}65 66Error Decompressor::decompress(MutableArrayRef<uint8_t> Output) {67 return compression::decompress(CompressionType,68 arrayRefFromStringRef(SectionData),69 Output.data(), Output.size());70}71