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