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to reflect the new license. We understand that people may be surprised that we're moving the header entirely to discuss the new license. We checked this carefully with the Foundation's lawyer and we believe this is the correct approach. Essentially, all code in the project is now made available by the LLVM project under our new license, so you will see that the license headers include that license only. Some of our contributors have contributed code under our old license, and accordingly, we have retained a copy of our old license notice in the top-level files in each project and repository. llvm-svn: 351636
94 lines
3.1 KiB
C++
94 lines
3.1 KiB
C++
//===-- Decompressor.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 "llvm/Object/Decompressor.h"
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#include "llvm/BinaryFormat/ELF.h"
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#include "llvm/Object/ELFObjectFile.h"
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#include "llvm/Support/Compression.h"
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#include "llvm/Support/DataExtractor.h"
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#include "llvm/Support/Endian.h"
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using namespace llvm;
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using namespace llvm::support::endian;
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using namespace object;
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Expected<Decompressor> Decompressor::create(StringRef Name, StringRef Data,
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bool IsLE, bool Is64Bit) {
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if (!zlib::isAvailable())
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return createError("zlib is not available");
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Decompressor D(Data);
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Error Err = isGnuStyle(Name) ? D.consumeCompressedGnuHeader()
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: D.consumeCompressedZLibHeader(Is64Bit, IsLE);
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if (Err)
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return std::move(Err);
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return D;
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}
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Decompressor::Decompressor(StringRef Data)
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: SectionData(Data), DecompressedSize(0) {}
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Error Decompressor::consumeCompressedGnuHeader() {
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if (!SectionData.startswith("ZLIB"))
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return createError("corrupted compressed section header");
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SectionData = SectionData.substr(4);
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// Consume uncompressed section size (big-endian 8 bytes).
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if (SectionData.size() < 8)
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return createError("corrupted uncompressed section size");
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DecompressedSize = read64be(SectionData.data());
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SectionData = SectionData.substr(8);
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return Error::success();
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}
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Error Decompressor::consumeCompressedZLibHeader(bool Is64Bit,
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bool IsLittleEndian) {
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using namespace ELF;
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uint64_t HdrSize = Is64Bit ? sizeof(Elf64_Chdr) : sizeof(Elf32_Chdr);
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if (SectionData.size() < HdrSize)
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return createError("corrupted compressed section header");
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DataExtractor Extractor(SectionData, IsLittleEndian, 0);
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uint32_t Offset = 0;
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if (Extractor.getUnsigned(&Offset, Is64Bit ? sizeof(Elf64_Word)
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: sizeof(Elf32_Word)) !=
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ELFCOMPRESS_ZLIB)
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return createError("unsupported compression type");
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// Skip Elf64_Chdr::ch_reserved field.
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if (Is64Bit)
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Offset += sizeof(Elf64_Word);
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DecompressedSize = Extractor.getUnsigned(
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&Offset, Is64Bit ? sizeof(Elf64_Xword) : sizeof(Elf32_Word));
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SectionData = SectionData.substr(HdrSize);
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return Error::success();
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}
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bool Decompressor::isGnuStyle(StringRef Name) {
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return Name.startswith(".zdebug");
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}
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bool Decompressor::isCompressed(const object::SectionRef &Section) {
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StringRef Name;
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if (Section.getName(Name))
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return false;
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return Section.isCompressed() || isGnuStyle(Name);
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}
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bool Decompressor::isCompressedELFSection(uint64_t Flags, StringRef Name) {
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return (Flags & ELF::SHF_COMPRESSED) || isGnuStyle(Name);
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}
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Error Decompressor::decompress(MutableArrayRef<char> Buffer) {
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size_t Size = Buffer.size();
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return zlib::uncompress(SectionData, Buffer.data(), Size);
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}
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