| //===- COFFObjcopy.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 "COFFObjcopy.h" |
| #include "Buffer.h" |
| #include "CopyConfig.h" |
| #include "Object.h" |
| #include "Reader.h" |
| #include "Writer.h" |
| #include "llvm-objcopy.h" |
| |
| #include "llvm/Object/Binary.h" |
| #include "llvm/Object/COFF.h" |
| #include "llvm/Support/Errc.h" |
| #include "llvm/Support/JamCRC.h" |
| #include "llvm/Support/Path.h" |
| #include <cassert> |
| |
| namespace llvm { |
| namespace objcopy { |
| namespace coff { |
| |
| using namespace object; |
| using namespace COFF; |
| |
| static bool isDebugSection(const Section &Sec) { |
| return Sec.Name.startswith(".debug"); |
| } |
| |
| static uint64_t getNextRVA(const Object &Obj) { |
| if (Obj.getSections().empty()) |
| return 0; |
| const Section &Last = Obj.getSections().back(); |
| return alignTo(Last.Header.VirtualAddress + Last.Header.VirtualSize, |
| Obj.IsPE ? Obj.PeHeader.SectionAlignment : 1); |
| } |
| |
| static uint32_t getCRC32(StringRef Data) { |
| JamCRC CRC; |
| CRC.update(ArrayRef<char>(Data.data(), Data.size())); |
| // The CRC32 value needs to be complemented because the JamCRC dosn't |
| // finalize the CRC32 value. It also dosn't negate the initial CRC32 value |
| // but it starts by default at 0xFFFFFFFF which is the complement of zero. |
| return ~CRC.getCRC(); |
| } |
| |
| static std::vector<uint8_t> createGnuDebugLinkSectionContents(StringRef File) { |
| ErrorOr<std::unique_ptr<MemoryBuffer>> LinkTargetOrErr = |
| MemoryBuffer::getFile(File); |
| if (!LinkTargetOrErr) |
| error("'" + File + "': " + LinkTargetOrErr.getError().message()); |
| auto LinkTarget = std::move(*LinkTargetOrErr); |
| uint32_t CRC32 = getCRC32(LinkTarget->getBuffer()); |
| |
| StringRef FileName = sys::path::filename(File); |
| size_t CRCPos = alignTo(FileName.size() + 1, 4); |
| std::vector<uint8_t> Data(CRCPos + 4); |
| memcpy(Data.data(), FileName.data(), FileName.size()); |
| support::endian::write32le(Data.data() + CRCPos, CRC32); |
| return Data; |
| } |
| |
| static void addGnuDebugLink(Object &Obj, StringRef DebugLinkFile) { |
| uint32_t StartRVA = getNextRVA(Obj); |
| |
| std::vector<Section> Sections; |
| Section Sec; |
| Sec.setOwnedContents(createGnuDebugLinkSectionContents(DebugLinkFile)); |
| Sec.Name = ".gnu_debuglink"; |
| Sec.Header.VirtualSize = Sec.getContents().size(); |
| Sec.Header.VirtualAddress = StartRVA; |
| Sec.Header.SizeOfRawData = alignTo(Sec.Header.VirtualSize, |
| Obj.IsPE ? Obj.PeHeader.FileAlignment : 1); |
| // Sec.Header.PointerToRawData is filled in by the writer. |
| Sec.Header.PointerToRelocations = 0; |
| Sec.Header.PointerToLinenumbers = 0; |
| // Sec.Header.NumberOfRelocations is filled in by the writer. |
| Sec.Header.NumberOfLinenumbers = 0; |
| Sec.Header.Characteristics = IMAGE_SCN_CNT_INITIALIZED_DATA | |
| IMAGE_SCN_MEM_READ | IMAGE_SCN_MEM_DISCARDABLE; |
| Sections.push_back(Sec); |
| Obj.addSections(Sections); |
| } |
| |
| static Error handleArgs(const CopyConfig &Config, Object &Obj) { |
| // Perform the actual section removals. |
| Obj.removeSections([&Config](const Section &Sec) { |
| // Contrary to --only-keep-debug, --only-section fully removes sections that |
| // aren't mentioned. |
| if (!Config.OnlySection.empty() && |
| !is_contained(Config.OnlySection, Sec.Name)) |
| return true; |
| |
| if (Config.StripDebug || Config.StripAll || Config.StripAllGNU || |
| Config.DiscardMode == DiscardType::All || Config.StripUnneeded) { |
| if (isDebugSection(Sec) && |
| (Sec.Header.Characteristics & IMAGE_SCN_MEM_DISCARDABLE) != 0) |
| return true; |
| } |
| |
| if (is_contained(Config.ToRemove, Sec.Name)) |
| return true; |
| |
| return false; |
| }); |
| |
| if (Config.OnlyKeepDebug) { |
| // For --only-keep-debug, we keep all other sections, but remove their |
| // content. The VirtualSize field in the section header is kept intact. |
| Obj.truncateSections([](const Section &Sec) { |
| return !isDebugSection(Sec) && Sec.Name != ".buildid" && |
| ((Sec.Header.Characteristics & |
| (IMAGE_SCN_CNT_CODE | IMAGE_SCN_CNT_INITIALIZED_DATA)) != 0); |
| }); |
| } |
| |
| // StripAll removes all symbols and thus also removes all relocations. |
| if (Config.StripAll || Config.StripAllGNU) |
| for (Section &Sec : Obj.getMutableSections()) |
| Sec.Relocs.clear(); |
| |
| // If we need to do per-symbol removals, initialize the Referenced field. |
| if (Config.StripUnneeded || Config.DiscardMode == DiscardType::All || |
| !Config.SymbolsToRemove.empty()) |
| if (Error E = Obj.markSymbols()) |
| return E; |
| |
| // Actually do removals of symbols. |
| Obj.removeSymbols([&](const Symbol &Sym) { |
| // For StripAll, all relocations have been stripped and we remove all |
| // symbols. |
| if (Config.StripAll || Config.StripAllGNU) |
| return true; |
| |
| if (is_contained(Config.SymbolsToRemove, Sym.Name)) { |
| // Explicitly removing a referenced symbol is an error. |
| if (Sym.Referenced) |
| reportError(Config.OutputFilename, |
| createStringError(llvm::errc::invalid_argument, |
| "not stripping symbol '%s' because it is " |
| "named in a relocation.", |
| Sym.Name.str().c_str())); |
| return true; |
| } |
| |
| if (!Sym.Referenced) { |
| // With --strip-unneeded, GNU objcopy removes all unreferenced local |
| // symbols, and any unreferenced undefined external. |
| // With --strip-unneeded-symbol we strip only specific unreferenced |
| // local symbol instead of removing all of such. |
| if (Sym.Sym.StorageClass == IMAGE_SYM_CLASS_STATIC || |
| Sym.Sym.SectionNumber == 0) |
| if (Config.StripUnneeded || |
| is_contained(Config.UnneededSymbolsToRemove, Sym.Name)) |
| return true; |
| |
| // GNU objcopy keeps referenced local symbols and external symbols |
| // if --discard-all is set, similar to what --strip-unneeded does, |
| // but undefined local symbols are kept when --discard-all is set. |
| if (Config.DiscardMode == DiscardType::All && |
| Sym.Sym.StorageClass == IMAGE_SYM_CLASS_STATIC && |
| Sym.Sym.SectionNumber != 0) |
| return true; |
| } |
| |
| return false; |
| }); |
| |
| if (!Config.AddGnuDebugLink.empty()) |
| addGnuDebugLink(Obj, Config.AddGnuDebugLink); |
| |
| if (!Config.BuildIdLinkDir.empty() || Config.BuildIdLinkInput || |
| Config.BuildIdLinkOutput || !Config.SplitDWO.empty() || |
| !Config.SymbolsPrefix.empty() || !Config.AddSection.empty() || |
| !Config.DumpSection.empty() || !Config.KeepSection.empty() || |
| !Config.SymbolsToGlobalize.empty() || !Config.SymbolsToKeep.empty() || |
| !Config.SymbolsToLocalize.empty() || !Config.SymbolsToWeaken.empty() || |
| !Config.SymbolsToKeepGlobal.empty() || !Config.SectionsToRename.empty() || |
| !Config.SetSectionFlags.empty() || !Config.SymbolsToRename.empty() || |
| Config.ExtractDWO || Config.KeepFileSymbols || Config.LocalizeHidden || |
| Config.PreserveDates || Config.StripDWO || Config.StripNonAlloc || |
| Config.StripSections || Config.Weaken || Config.DecompressDebugSections || |
| Config.DiscardMode == DiscardType::Locals || |
| !Config.SymbolsToAdd.empty() || Config.EntryExpr) { |
| return createStringError(llvm::errc::invalid_argument, |
| "Option not supported by llvm-objcopy for COFF"); |
| } |
| |
| return Error::success(); |
| } |
| |
| Error executeObjcopyOnBinary(const CopyConfig &Config, COFFObjectFile &In, |
| Buffer &Out) { |
| COFFReader Reader(In); |
| Expected<std::unique_ptr<Object>> ObjOrErr = Reader.create(); |
| if (!ObjOrErr) |
| return createFileError(Config.InputFilename, ObjOrErr.takeError()); |
| Object *Obj = ObjOrErr->get(); |
| assert(Obj && "Unable to deserialize COFF object"); |
| if (Error E = handleArgs(Config, *Obj)) |
| return createFileError(Config.InputFilename, std::move(E)); |
| COFFWriter Writer(*Obj, Out); |
| if (Error E = Writer.write()) |
| return createFileError(Config.OutputFilename, std::move(E)); |
| return Error::success(); |
| } |
| |
| } // end namespace coff |
| } // end namespace objcopy |
| } // end namespace llvm |