Reland "[lld-macho] Implement -load_hidden"
This flag was introduced in ld64-609. It instructs the linker to link to a static library while treating its symbols as if they had hidden visibility. This is useful when building a dylib that links to static libraries but we don't want the symbols from those to be exported. Closes #51505 This reland adds bitcode file handling, so we won't get any compile errors due to BitcodeFile::forceHidden being unused. Differential Revision: https://reviews.llvm.org/D130473
This commit is contained in:
Daniel Bertalan
parent
8fbc3c1179
commit
595fc59f74
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@ -266,7 +266,8 @@ static DenseMap<StringRef, ArchiveFileInfo> loadedArchives;
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static InputFile *addFile(StringRef path, LoadType loadType,
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bool isLazy = false, bool isExplicit = true,
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bool isBundleLoader = false) {
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bool isBundleLoader = false,
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bool isForceHidden = false) {
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Optional<MemoryBufferRef> buffer = readFile(path);
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if (!buffer)
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return nullptr;
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@ -293,7 +294,7 @@ static InputFile *addFile(StringRef path, LoadType loadType,
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if (!archive->isEmpty() && !archive->hasSymbolTable())
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error(path + ": archive has no index; run ranlib to add one");
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file = make<ArchiveFile>(std::move(archive));
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file = make<ArchiveFile>(std::move(archive), isForceHidden);
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} else {
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file = entry->second.file;
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// Command-line loads take precedence. If file is previously loaded via
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@ -1035,6 +1036,11 @@ static void createFiles(const InputArgList &args) {
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case OPT_force_load:
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addFile(rerootPath(arg->getValue()), LoadType::CommandLineForce);
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break;
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case OPT_load_hidden:
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addFile(rerootPath(arg->getValue()), LoadType::CommandLine,
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/*isLazy=*/false, /*isExplicit=*/true, /*isBundleLoader=*/false,
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/*isForceHidden=*/true);
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break;
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case OPT_l:
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case OPT_needed_l:
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case OPT_reexport_l:
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@ -150,6 +150,7 @@ std::string macho::createResponseFile(const InputArgList &args) {
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break;
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case OPT_force_load:
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case OPT_weak_library:
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case OPT_load_hidden:
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os << arg->getSpelling() << " "
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<< quote(rewriteInputPath(arg->getValue())) << "\n";
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break;
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@ -768,7 +768,7 @@ void ObjFile::parseRelocations(ArrayRef<SectionHeader> sectionHeaders,
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template <class NList>
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static macho::Symbol *createDefined(const NList &sym, StringRef name,
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InputSection *isec, uint64_t value,
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uint64_t size) {
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uint64_t size, bool forceHidden) {
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// Symbol scope is determined by sym.n_type & (N_EXT | N_PEXT):
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// N_EXT: Global symbols. These go in the symbol table during the link,
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// and also in the export table of the output so that the dynamic
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@ -787,7 +787,10 @@ static macho::Symbol *createDefined(const NList &sym, StringRef name,
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(sym.n_desc & (N_WEAK_DEF | N_WEAK_REF)) == (N_WEAK_DEF | N_WEAK_REF);
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if (sym.n_type & N_EXT) {
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bool isPrivateExtern = sym.n_type & N_PEXT;
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// -load_hidden makes us treat global symbols as linkage unit scoped.
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// Duplicates are reported but the symbol does not go in the export trie.
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bool isPrivateExtern = sym.n_type & N_PEXT || forceHidden;
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// lld's behavior for merging symbols is slightly different from ld64:
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// ld64 picks the winning symbol based on several criteria (see
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// pickBetweenRegularAtoms() in ld64's SymbolTable.cpp), while lld
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@ -844,11 +847,12 @@ static macho::Symbol *createDefined(const NList &sym, StringRef name,
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// InputSection. They cannot be weak.
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template <class NList>
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static macho::Symbol *createAbsolute(const NList &sym, InputFile *file,
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StringRef name) {
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StringRef name, bool forceHidden) {
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if (sym.n_type & N_EXT) {
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bool isPrivateExtern = sym.n_type & N_PEXT || forceHidden;
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return symtab->addDefined(
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name, file, nullptr, sym.n_value, /*size=*/0,
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/*isWeakDef=*/false, sym.n_type & N_PEXT, sym.n_desc & N_ARM_THUMB_DEF,
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/*isWeakDef=*/false, isPrivateExtern, sym.n_desc & N_ARM_THUMB_DEF,
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/*isReferencedDynamically=*/false, sym.n_desc & N_NO_DEAD_STRIP,
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/*isWeakDefCanBeHidden=*/false);
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}
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@ -864,15 +868,16 @@ template <class NList>
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macho::Symbol *ObjFile::parseNonSectionSymbol(const NList &sym,
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StringRef name) {
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uint8_t type = sym.n_type & N_TYPE;
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bool isPrivateExtern = sym.n_type & N_PEXT || forceHidden;
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switch (type) {
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case N_UNDF:
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return sym.n_value == 0
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? symtab->addUndefined(name, this, sym.n_desc & N_WEAK_REF)
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: symtab->addCommon(name, this, sym.n_value,
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1 << GET_COMM_ALIGN(sym.n_desc),
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sym.n_type & N_PEXT);
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isPrivateExtern);
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case N_ABS:
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return createAbsolute(sym, this, name);
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return createAbsolute(sym, this, name, forceHidden);
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case N_PBUD:
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case N_INDR:
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error("TODO: support symbols of type " + std::to_string(type));
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@ -944,7 +949,8 @@ void ObjFile::parseSymbols(ArrayRef<typename LP::section> sectionHeaders,
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" at misaligned offset");
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continue;
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}
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symbols[symIndex] = createDefined(sym, name, isec, 0, isec->getSize());
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symbols[symIndex] =
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createDefined(sym, name, isec, 0, isec->getSize(), forceHidden);
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}
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continue;
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}
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@ -979,8 +985,8 @@ void ObjFile::parseSymbols(ArrayRef<typename LP::section> sectionHeaders,
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// 4. If we have a literal section (e.g. __cstring and __literal4).
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if (!subsectionsViaSymbols || symbolOffset == 0 ||
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sym.n_desc & N_ALT_ENTRY || !isa<ConcatInputSection>(isec)) {
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symbols[symIndex] =
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createDefined(sym, name, isec, symbolOffset, symbolSize);
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symbols[symIndex] = createDefined(sym, name, isec, symbolOffset,
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symbolSize, forceHidden);
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continue;
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}
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auto *concatIsec = cast<ConcatInputSection>(isec);
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@ -998,8 +1004,8 @@ void ObjFile::parseSymbols(ArrayRef<typename LP::section> sectionHeaders,
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// By construction, the symbol will be at offset zero in the new
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// subsection.
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symbols[symIndex] =
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createDefined(sym, name, nextIsec, /*value=*/0, symbolSize);
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symbols[symIndex] = createDefined(sym, name, nextIsec, /*value=*/0,
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symbolSize, forceHidden);
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// TODO: ld64 appears to preserve the original alignment as well as each
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// subsection's offset from the last aligned address. We should consider
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// emulating that behavior.
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@ -1036,8 +1042,8 @@ OpaqueFile::OpaqueFile(MemoryBufferRef mb, StringRef segName,
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}
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ObjFile::ObjFile(MemoryBufferRef mb, uint32_t modTime, StringRef archiveName,
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bool lazy)
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: InputFile(ObjKind, mb, lazy), modTime(modTime) {
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bool lazy, bool forceHidden)
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: InputFile(ObjKind, mb, lazy), modTime(modTime), forceHidden(forceHidden) {
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this->archiveName = std::string(archiveName);
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if (lazy) {
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if (target->wordSize == 8)
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@ -2061,26 +2067,27 @@ void DylibFile::checkAppExtensionSafety(bool dylibIsAppExtensionSafe) const {
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warn("using '-application_extension' with unsafe dylib: " + toString(this));
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}
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ArchiveFile::ArchiveFile(std::unique_ptr<object::Archive> &&f)
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: InputFile(ArchiveKind, f->getMemoryBufferRef()), file(std::move(f)) {}
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ArchiveFile::ArchiveFile(std::unique_ptr<object::Archive> &&f, bool forceHidden)
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: InputFile(ArchiveKind, f->getMemoryBufferRef()), file(std::move(f)),
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forceHidden(forceHidden) {}
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void ArchiveFile::addLazySymbols() {
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for (const object::Archive::Symbol &sym : file->symbols())
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symtab->addLazyArchive(sym.getName(), this, sym);
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}
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static Expected<InputFile *> loadArchiveMember(MemoryBufferRef mb,
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uint32_t modTime,
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StringRef archiveName,
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uint64_t offsetInArchive) {
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static Expected<InputFile *>
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loadArchiveMember(MemoryBufferRef mb, uint32_t modTime, StringRef archiveName,
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uint64_t offsetInArchive, bool forceHidden) {
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if (config->zeroModTime)
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modTime = 0;
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switch (identify_magic(mb.getBuffer())) {
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case file_magic::macho_object:
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return make<ObjFile>(mb, modTime, archiveName);
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return make<ObjFile>(mb, modTime, archiveName, /*lazy=*/false, forceHidden);
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case file_magic::bitcode:
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return make<BitcodeFile>(mb, archiveName, offsetInArchive);
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return make<BitcodeFile>(mb, archiveName, offsetInArchive, /*lazy=*/false,
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forceHidden);
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default:
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return createStringError(inconvertibleErrorCode(),
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mb.getBufferIdentifier() +
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@ -2104,8 +2111,8 @@ Error ArchiveFile::fetch(const object::Archive::Child &c, StringRef reason) {
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if (!modTime)
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return modTime.takeError();
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Expected<InputFile *> file =
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loadArchiveMember(*mb, toTimeT(*modTime), getName(), c.getChildOffset());
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Expected<InputFile *> file = loadArchiveMember(
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*mb, toTimeT(*modTime), getName(), c.getChildOffset(), forceHidden);
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if (!file)
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return file.takeError();
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@ -2153,7 +2160,8 @@ static macho::Symbol *createBitcodeSymbol(const lto::InputFile::Symbol &objSym,
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case GlobalValue::DefaultVisibility:
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break;
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}
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isPrivateExtern = isPrivateExtern || objSym.canBeOmittedFromSymbolTable();
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isPrivateExtern = isPrivateExtern || objSym.canBeOmittedFromSymbolTable() ||
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file.forceHidden;
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if (objSym.isCommon())
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return symtab->addCommon(name, &file, objSym.getCommonSize(),
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@ -2168,8 +2176,8 @@ static macho::Symbol *createBitcodeSymbol(const lto::InputFile::Symbol &objSym,
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}
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BitcodeFile::BitcodeFile(MemoryBufferRef mb, StringRef archiveName,
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uint64_t offsetInArchive, bool lazy)
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: InputFile(BitcodeKind, mb, lazy) {
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uint64_t offsetInArchive, bool lazy, bool forceHidden)
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: InputFile(BitcodeKind, mb, lazy), forceHidden(forceHidden) {
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this->archiveName = std::string(archiveName);
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std::string path = mb.getBufferIdentifier().str();
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// ThinLTO assumes that all MemoryBufferRefs given to it have a unique
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@ -156,7 +156,7 @@ struct FDE {
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class ObjFile final : public InputFile {
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public:
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ObjFile(MemoryBufferRef mb, uint32_t modTime, StringRef archiveName,
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bool lazy = false);
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bool lazy = false, bool forceHidden = false);
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ArrayRef<llvm::MachO::data_in_code_entry> getDataInCode() const;
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template <class LP> void parse();
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@ -171,6 +171,7 @@ public:
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std::unique_ptr<lld::DWARFCache> dwarfCache;
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Section *addrSigSection = nullptr;
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const uint32_t modTime;
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bool forceHidden;
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std::vector<ConcatInputSection *> debugSections;
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std::vector<CallGraphEntry> callGraph;
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llvm::DenseMap<ConcatInputSection *, FDE> fdes;
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@ -259,7 +260,8 @@ private:
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// .a file
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class ArchiveFile final : public InputFile {
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public:
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explicit ArchiveFile(std::unique_ptr<llvm::object::Archive> &&file);
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explicit ArchiveFile(std::unique_ptr<llvm::object::Archive> &&file,
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bool forceHidden);
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void addLazySymbols();
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void fetch(const llvm::object::Archive::Symbol &);
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// LLD normally doesn't use Error for error-handling, but the underlying
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@ -273,16 +275,20 @@ private:
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// Keep track of children fetched from the archive by tracking
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// which address offsets have been fetched already.
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llvm::DenseSet<uint64_t> seen;
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// Load all symbols with hidden visibility (-load_hidden).
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bool forceHidden;
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};
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class BitcodeFile final : public InputFile {
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public:
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explicit BitcodeFile(MemoryBufferRef mb, StringRef archiveName,
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uint64_t offsetInArchive, bool lazy = false);
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uint64_t offsetInArchive, bool lazy = false,
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bool forceHidden = false);
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static bool classof(const InputFile *f) { return f->kind() == BitcodeKind; }
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void parse();
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std::unique_ptr<llvm::lto::InputFile> obj;
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bool forceHidden;
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private:
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void parseLazy();
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@ -240,6 +240,10 @@ def force_load : Separate<["-"], "force_load">,
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def force_load_swift_libs : Flag<["-"], "force_load_swift_libs">,
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HelpText<"Apply -force_load to libraries listed in LC_LINKER_OPTIONS whose names start with 'swift'">,
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Group<grp_libs>;
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def load_hidden : Separate<["-"], "load_hidden">,
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MetaVarName<"<path>">,
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HelpText<"Load all symbols from static library with hidden visibility">,
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Group<grp_libs>;
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def grp_content : OptionGroup<"content">, HelpText<"ADDITIONAL CONTENT">;
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@ -0,0 +1,28 @@
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; REQUIRES: x86
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; RUN: rm -rf %t; split-file %s %t
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; RUN: llvm-as %t/archive.ll -o %t/archive.o
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; RUN: llvm-ar rcs %t/archive.a %t/archive.o
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; RUN: llvm-as %t/obj.ll -o %t/obj.o
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; RUN: %lld -dylib -lSystem %t/obj.o -load_hidden %t/archive.a -o %t/test.dylib
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; RUN: llvm-nm %t/test.dylib | FileCheck %s
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; CHECK: t _foo
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;--- archive.ll
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target triple = "x86_64-apple-macosx10.15.0"
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target datalayout = "e-m:o-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
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define void @foo() noinline optnone {
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ret void
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}
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;--- obj.ll
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target triple = "x86_64-apple-macosx10.15.0"
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target datalayout = "e-m:o-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
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declare void @foo();
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define void @main() {
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call void @foo()
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ret void
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}
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@ -0,0 +1,72 @@
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# REQUIRES: x86
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# RUN: rm -rf %t; split-file %s %t
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# RUN: llvm-mc -filetype=obj -triple=x86_64-apple-darwin %t/archive-foo.s -o %t/archive-foo.o
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# RUN: llvm-mc -filetype=obj -triple=x86_64-apple-darwin %t/archive-baz.s -o %t/archive-baz.o
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# RUN: llvm-ar rcs %t/foo.a %t/archive-foo.o
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# RUN: llvm-ar rcs %t/baz.a %t/archive-baz.o
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# RUN: llvm-mc -filetype=obj -triple=x86_64-apple-darwin %t/obj.s -o %t/obj.o
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# RUN: llvm-mc -filetype=obj -triple=x86_64-apple-darwin %t/obj-bar.s -o %t/obj-bar.o
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# RUN: %lld -dylib -lSystem %t/obj.o -load_hidden %t/foo.a -o %t/test.dylib
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# RUN: llvm-nm %t/test.dylib | FileCheck %s
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# CHECK-DAG: t _foo
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# CHECK-DAG: d _bar
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## If an archive has already been loaded without -load_hidden earlier in the command line,
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## -load_hidden does not have an effect.
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# RUN: %lld -dylib -lSystem %t/obj.o %t/foo.a -load_hidden %t/foo.a -o %t/test-regular-then-hidden.dylib
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# RUN: llvm-nm %t/test-regular-then-hidden.dylib | FileCheck %s --check-prefix=REGULAR-THEN-HIDDEN
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# REGULAR-THEN-HIDDEN-DAG: T _foo
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# REGULAR-THEN-HIDDEN-DAG: D _bar
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## If -load_hidden comes first, the symbols will have hidden visibility.
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# RUN: %lld -dylib -lSystem %t/obj.o -load_hidden %t/foo.a %t/foo.a -o %t/test-hidden-then-regular.dylib
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# RUN: llvm-nm %t/test-hidden-then-regular.dylib | FileCheck %s --check-prefix=HIDDEN-THEN-REGULAR
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# HIDDEN-THEN-REGULAR-DAG: t _foo
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# HIDDEN-THEN-REGULAR-DAG: d _bar
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## If both -load_hidden and -force_load are specified, the earlier one will have an effect.
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# RUN: %lld -dylib -lSystem %t/obj.o %t/foo.a -force_load %t/baz.a -load_hidden %t/baz.a -o %t/test-force-then-hidden.dylib
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# RUN: llvm-nm %t/test-force-then-hidden.dylib | FileCheck %s --check-prefix=FORCE-THEN-HIDDEN
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# FORCE-THEN-HIDDEN: T _baz
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# RUN: %lld -dylib -lSystem %t/obj.o %t/foo.a -load_hidden %t/baz.a -force_load %t/baz.a -o %t/test-hidden-then-force.dylib
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# RUN: llvm-nm %t/test-hidden-then-force.dylib | FileCheck %s --check-prefix=HIDDEN-THEN-FORCE
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# HIDDEN-THEN-FORCE-NOT: _baz
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## -load_hidden does not cause the library to be loaded eagerly.
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# RUN: %lld -dylib -lSystem %t/obj.o -load_hidden %t/foo.a -load_hidden %t/baz.a -o %t/test-lazy.dylib
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# RUN: llvm-nm %t/test-lazy.dylib | FileCheck %s --check-prefix=LAZY
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# LAZY-NOT: _baz
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## Specifying the same library twice is fine.
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# RUN: %lld -dylib -lSystem %t/obj.o -load_hidden %t/foo.a -load_hidden %t/foo.a -o %t/test-twice.dylib
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# RUN: llvm-nm %t/test-twice.dylib | FileCheck %s --check-prefix=TWICE
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# TWICE-DAG: t _foo
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# TWICE-DAG: d _bar
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## -load_hidden causes the symbols to have "private external" visibility, so duplicate definitions
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## are not allowed.
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# RUN: not %lld -dylib -lSystem %t/obj.o %t/obj-bar.o -load_hidden %t/foo.a 2>&1 | FileCheck %s --check-prefix=DUP
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# DUP: error: duplicate symbol: _bar
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#--- archive-foo.s
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.globl _foo
|
||||
_foo:
|
||||
|
||||
.data
|
||||
.globl _bar
|
||||
_bar:
|
||||
|
||||
#--- archive-baz.s
|
||||
.globl _baz
|
||||
_baz:
|
||||
|
||||
#--- obj-bar.s
|
||||
.data
|
||||
.globl _bar
|
||||
_bar:
|
||||
|
||||
#--- obj.s
|
||||
.globl _test
|
||||
_test:
|
||||
call _foo
|
||||
|
|
@ -39,6 +39,10 @@
|
|||
# RUN: tar xf %t/repro4.tar -C %t
|
||||
# RUN: cd %t/repro4; %no-arg-lld @response.txt | FileCheck %s -DDIR="%:t/%:t"
|
||||
|
||||
# RUN: %lld --reproduce %t/repro7.tar -lSystem -syslibroot %t -force_load %t/foo.a -force_load %t/bar.a %t/test.o -o /dev/null -t | FileCheck %s -DDIR="%t/%:t"
|
||||
# RUN: tar xf %t/repro7.tar -C %t
|
||||
# RUN: cd %t/repro7; %no-arg-lld @response.txt | FileCheck %s -DDIR="%:t/%:t"
|
||||
|
||||
# RUN: echo "%t/libfoo.dylib" > %t/filelist
|
||||
# RUN: echo "%t/libbar.dylib" >> %t/filelist
|
||||
# RUN: %lld --reproduce %t/repro5.tar -lSystem -syslibroot %t -filelist %t/filelist %t/test.o -o /dev/null -t | FileCheck %s -DDIR="%t/%:t"
|
||||
|
|
|
|||
Loading…
Reference in New Issue