1
0
mirror of https://github.com/RPCS3/llvm-mirror.git synced 2024-11-23 03:02:36 +01:00
llvm-mirror/lib/Object/Decompressor.cpp
George Rimar 21610566c8 Recommit r368812 "[llvm/Object] - Convert SectionRef::getName() to return Expected<>"
Changes: no changes. A fix for the clang code will be landed right on top.

Original commit message:

SectionRef::getName() returns std::error_code now.
Returning Expected<> instead has multiple benefits.

For example, it forces user to check the error returned.
Also Expected<> may keep a valuable string error message,
what is more useful than having a error code.
(Object\invalid.test was updated to show the new messages printed.)

This patch makes a change for all users to switch to Expected<> version.

Note: in a few places the error returned was ignored before my changes.
In such places I left them ignored. My intention was to convert the interface
used, and not to improve and/or the existent users in this patch.
(Though I think this is good idea for a follow-ups to revisit such places
and either remove consumeError calls or comment each of them to clarify why
it is OK to have them).

Differential revision: https://reviews.llvm.org/D66089

llvm-svn: 368826
2019-08-14 11:10:11 +00:00

99 lines
3.2 KiB
C++

//===-- 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/ELFObjectFile.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) {
if (!zlib::isAvailable())
return createError("zlib is not available");
Decompressor D(Data);
Error Err = isGnuStyle(Name) ? D.consumeCompressedGnuHeader()
: D.consumeCompressedZLibHeader(Is64Bit, IsLE);
if (Err)
return std::move(Err);
return D;
}
Decompressor::Decompressor(StringRef Data)
: SectionData(Data), DecompressedSize(0) {}
Error Decompressor::consumeCompressedGnuHeader() {
if (!SectionData.startswith("ZLIB"))
return createError("corrupted compressed section header");
SectionData = SectionData.substr(4);
// Consume uncompressed section size (big-endian 8 bytes).
if (SectionData.size() < 8)
return createError("corrupted uncompressed section size");
DecompressedSize = read64be(SectionData.data());
SectionData = SectionData.substr(8);
return Error::success();
}
Error Decompressor::consumeCompressedZLibHeader(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;
if (Extractor.getUnsigned(&Offset, Is64Bit ? sizeof(Elf64_Word)
: sizeof(Elf32_Word)) !=
ELFCOMPRESS_ZLIB)
return createError("unsupported compression type");
// 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();
}
bool Decompressor::isGnuStyle(StringRef Name) {
return Name.startswith(".zdebug");
}
bool Decompressor::isCompressed(const object::SectionRef &Section) {
if (Section.isCompressed())
return true;
Expected<StringRef> SecNameOrErr = Section.getName();
if (SecNameOrErr)
return isGnuStyle(*SecNameOrErr);
consumeError(SecNameOrErr.takeError());
return false;
}
bool Decompressor::isCompressedELFSection(uint64_t Flags, StringRef Name) {
return (Flags & ELF::SHF_COMPRESSED) || isGnuStyle(Name);
}
Error Decompressor::decompress(MutableArrayRef<char> Buffer) {
size_t Size = Buffer.size();
return zlib::uncompress(SectionData, Buffer.data(), Size);
}