14726cd11b
Unable to add a unit test for this, as there is only one local undefined symbol in regular shared libraries without a name. llvm-svn: 232867
124 lines
3.9 KiB
C++
124 lines
3.9 KiB
C++
//===- lib/ReaderWriter/ELF/DynamicFile.h ---------------------------------===//
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//
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// The LLVM Linker
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLD_READER_WRITER_ELF_DYNAMIC_FILE_H
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#define LLD_READER_WRITER_ELF_DYNAMIC_FILE_H
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#include "Atoms.h"
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#include "lld/Core/SharedLibraryFile.h"
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#include "lld/ReaderWriter/ELFLinkingContext.h"
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#include "llvm/Object/ELF.h"
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#include "llvm/Support/Path.h"
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#include <unordered_map>
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namespace lld {
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namespace elf {
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template <class ELFT> class DynamicFile : public SharedLibraryFile {
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public:
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static ErrorOr<std::unique_ptr<DynamicFile>>
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create(std::unique_ptr<llvm::MemoryBuffer> mb, ELFLinkingContext &ctx);
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const SharedLibraryAtom *exports(StringRef name,
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bool dataSymbolOnly) const override {
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assert(!dataSymbolOnly && "Invalid option for ELF exports!");
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// See if we have the symbol.
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auto sym = _nameToSym.find(name);
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if (sym == _nameToSym.end())
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return nullptr;
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// Have we already created a SharedLibraryAtom for it?
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if (sym->second._atom)
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return sym->second._atom;
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// Create a SharedLibraryAtom for this symbol.
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return sym->second._atom = new (_alloc) ELFDynamicAtom<ELFT>(
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*this, name, _soname, sym->second._symbol);
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}
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StringRef getDSOName() const override { return _soname; }
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protected:
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std::error_code doParse() override {
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std::error_code ec;
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_objFile.reset(
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new llvm::object::ELFFile<ELFT>(_mb->getBuffer(), ec));
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if (ec)
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return ec;
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llvm::object::ELFFile<ELFT> &obj = *_objFile;
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_soname = obj.getLoadName();
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if (_soname.empty())
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_soname = llvm::sys::path::filename(path());
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// Create a map from names to dynamic symbol table entries.
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// TODO: This should use the object file's build in hash table instead if
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// it exists.
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for (auto i = obj.begin_dynamic_symbols(), e = obj.end_dynamic_symbols();
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i != e; ++i) {
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auto name = obj.getSymbolName(i);
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if ((ec = name.getError()))
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return ec;
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// Dont add local symbols to dynamic entries. The first symbol in the
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// dynamic symbol table is a local symbol.
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if (i->getBinding() == llvm::ELF::STB_LOCAL)
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continue;
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// TODO: Add absolute symbols
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if (i->st_shndx == llvm::ELF::SHN_ABS)
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continue;
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if (i->st_shndx == llvm::ELF::SHN_UNDEF) {
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if (!_useShlibUndefines)
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continue;
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// Create an undefined atom.
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if (!name->empty()) {
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auto *newAtom = new (_alloc) ELFUndefinedAtom<ELFT>(*this, *name, &*i);
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_undefinedAtoms._atoms.push_back(newAtom);
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}
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continue;
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}
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_nameToSym[*name]._symbol = &*i;
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}
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return std::error_code();
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}
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private:
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DynamicFile(std::unique_ptr<MemoryBuffer> mb, ELFLinkingContext &ctx)
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: SharedLibraryFile(mb->getBufferIdentifier()), _mb(std::move(mb)),
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_ctx(ctx), _useShlibUndefines(ctx.useShlibUndefines()) {}
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mutable llvm::BumpPtrAllocator _alloc;
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std::unique_ptr<llvm::object::ELFFile<ELFT>> _objFile;
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/// \brief DT_SONAME
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StringRef _soname;
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struct SymAtomPair {
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SymAtomPair() : _symbol(nullptr), _atom(nullptr) {}
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const typename llvm::object::ELFFile<ELFT>::Elf_Sym *_symbol;
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const SharedLibraryAtom *_atom;
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};
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std::unique_ptr<MemoryBuffer> _mb;
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ELFLinkingContext &_ctx;
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bool _useShlibUndefines;
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mutable std::unordered_map<StringRef, SymAtomPair> _nameToSym;
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};
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template <class ELFT>
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ErrorOr<std::unique_ptr<DynamicFile<ELFT>>>
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DynamicFile<ELFT>::create(std::unique_ptr<llvm::MemoryBuffer> mb,
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ELFLinkingContext &ctx) {
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return std::unique_ptr<DynamicFile>(new DynamicFile(std::move(mb), ctx));
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}
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} // end namespace elf
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} // end namespace lld
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#endif
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