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//===- Core/File.h - A Container of Atoms ---------------------------------===//
// The LLVM Linker
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
#include "lld/Core/AbsoluteAtom.h"
#include "lld/Core/DefinedAtom.h"
#include "lld/Core/SharedLibraryAtom.h"
#include "lld/Core/UndefinedAtom.h"
#include "llvm/ADT/Optional.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/Twine.h"
#include "llvm/Support/ErrorHandling.h"
#include <functional>
#include <memory>
#include <mutex>
#include <vector>
namespace lld {
class LinkingContext;
/// Every Atom is owned by some File. A common scenario is for a single
/// object file (.o) to be parsed by some reader and produce a single
/// File object that represents the content of that object file.
/// To iterate through the Atoms in a File there are four methods that
/// return collections. For instance to iterate through all the DefinedAtoms
/// in a File object use:
/// for (const DefinedAtoms *atom : file->defined()) {
/// }
/// The Atom objects in a File are owned by the File object. The Atom objects
/// are destroyed when the File object is destroyed.
class File {
virtual ~File();
/// Kinds of files that are supported.
enum Kind {
kindErrorObject, ///< a error object file (.o)
kindNormalizedObject, ///< a normalized file (.o)
kindMachObject, ///< a MachO object file (.o)
kindCEntryObject, ///< a file for CEntries
kindHeaderObject, ///< a file for file headers
kindEntryObject, ///< a file for the entry
kindUndefinedSymsObject, ///< a file for undefined symbols
kindStubHelperObject, ///< a file for stub helpers
kindResolverMergedObject, ///< the resolver merged file.
kindSectCreateObject, ///< a sect create object file (.o)
kindSharedLibrary, ///< shared library (.so)
kindArchiveLibrary ///< archive (.a)
/// Returns file kind. Need for dyn_cast<> on File objects.
Kind kind() const {
return _kind;
/// This returns the path to the file which was used to create this object
/// (e.g. "/tmp/foo.o"). If the file is a member of an archive file, the
/// returned string includes the archive file name.
StringRef path() const {
if (_archivePath.empty())
return _path;
if (_archiveMemberPath.empty())
_archiveMemberPath = (_archivePath + "(" + _path + ")").str();
return _archiveMemberPath;
/// Returns the path of the archive file name if this file is instantiated
/// from an archive file. Otherwise returns the empty string.
StringRef archivePath() const { return _archivePath; }
void setArchivePath(StringRef path) { _archivePath = path; }
/// Returns the path name of this file. It doesn't include archive file name.
StringRef memberPath() const { return _path; }
/// Returns the command line order of the file.
uint64_t ordinal() const {
assert(_ordinal != UINT64_MAX);
return _ordinal;
/// Returns true/false depending on whether an ordinal has been set.
bool hasOrdinal() const { return (_ordinal != UINT64_MAX); }
/// Sets the command line order of the file.
void setOrdinal(uint64_t ordinal) const { _ordinal = ordinal; }
/// Returns the ordinal for the next atom to be defined in this file.
uint64_t getNextAtomOrdinalAndIncrement() const {
return _nextAtomOrdinal++;
/// For allocating any objects owned by this File.
llvm::BumpPtrAllocator &allocator() const {
return _allocator;
/// The type of atom mutable container.
template <typename T> using AtomVector = std::vector<OwningAtomPtr<T>>;
/// The range type for the atoms.
template <typename T> class AtomRange {
AtomRange(AtomVector<T> &v) : _v(v) {}
AtomRange(const AtomVector<T> &v) : _v(const_cast<AtomVector<T> &>(v)) {}
using ConstDerefFn = const T* (*)(const OwningAtomPtr<T>&);
using DerefFn = T* (*)(OwningAtomPtr<T>&);
typedef llvm::mapped_iterator<typename AtomVector<T>::const_iterator,
ConstDerefFn> ConstItTy;
typedef llvm::mapped_iterator<typename AtomVector<T>::iterator,
DerefFn> ItTy;
static const T* DerefConst(const OwningAtomPtr<T> &p) {
return p.get();
static T* Deref(OwningAtomPtr<T> &p) {
return p.get();
ConstItTy begin() const {
return ConstItTy(_v.begin(), ConstDerefFn(DerefConst));
ConstItTy end() const {
return ConstItTy(_v.end(), ConstDerefFn(DerefConst));
ItTy begin() {
return ItTy(_v.begin(), DerefFn(Deref));
ItTy end() {
return ItTy(_v.end(), DerefFn(Deref));
llvm::iterator_range<typename AtomVector<T>::iterator> owning_ptrs() {
return llvm::make_range(_v.begin(), _v.end());
llvm::iterator_range<typename AtomVector<T>::iterator> owning_ptrs() const {
return llvm::make_range(_v.begin(), _v.end());
bool empty() const {
return _v.empty();
size_t size() const {
return _v.size();
const OwningAtomPtr<T> &operator[](size_t idx) const {
return _v[idx];
OwningAtomPtr<T> &operator[](size_t idx) {
return _v[idx];
AtomVector<T> &_v;
/// Must be implemented to return the AtomVector object for
/// all DefinedAtoms in this File.
virtual const AtomRange<DefinedAtom> defined() const = 0;
/// Must be implemented to return the AtomVector object for
/// all UndefinedAtomw in this File.
virtual const AtomRange<UndefinedAtom> undefined() const = 0;
/// Must be implemented to return the AtomVector object for
/// all SharedLibraryAtoms in this File.
virtual const AtomRange<SharedLibraryAtom> sharedLibrary() const = 0;
/// Must be implemented to return the AtomVector object for
/// all AbsoluteAtoms in this File.
virtual const AtomRange<AbsoluteAtom> absolute() const = 0;
/// Drop all of the atoms owned by this file. This will result in all of
/// the atoms running their destructors.
/// This is required because atoms may be allocated on a BumpPtrAllocator
/// of a different file. We need to destruct all atoms before any files.
virtual void clearAtoms() = 0;
/// If a file is parsed using a different method than doParse(),
/// one must use this method to set the last error status, so that
/// doParse will not be called twice. Only YAML reader uses this
/// (because YAML reader does not read blobs but structured data).
void setLastError(std::error_code err) { _lastError = err; }
std::error_code parse();
// Usually each file owns a std::unique_ptr<MemoryBuffer>.
// However, there's one special case. If a file is an archive file,
// the archive file and its children all shares the same memory buffer.
// This method is used by the ArchiveFile to give its children
// co-ownership of the buffer.
void setSharedMemoryBuffer(std::shared_ptr<MemoryBuffer> mb) {
_sharedMemoryBuffer = mb;
/// only subclasses of File can be instantiated
File(StringRef p, Kind kind)
: _path(p), _kind(kind), _ordinal(UINT64_MAX),
_nextAtomOrdinal(0) {}
/// Subclasses should override this method to parse the
/// memory buffer passed to this file's constructor.
virtual std::error_code doParse() { return std::error_code(); }
static AtomVector<DefinedAtom> _noDefinedAtoms;
static AtomVector<UndefinedAtom> _noUndefinedAtoms;
static AtomVector<SharedLibraryAtom> _noSharedLibraryAtoms;
static AtomVector<AbsoluteAtom> _noAbsoluteAtoms;
mutable llvm::BumpPtrAllocator _allocator;
StringRef _path;
std::string _archivePath;
mutable std::string _archiveMemberPath;
Kind _kind;
mutable uint64_t _ordinal;
mutable uint64_t _nextAtomOrdinal;
std::shared_ptr<MemoryBuffer> _sharedMemoryBuffer;
llvm::Optional<std::error_code> _lastError;
std::mutex _parseMutex;
/// An ErrorFile represents a file that doesn't exist.
/// If you try to parse a file which doesn't exist, an instance of this
/// class will be returned. That's parse method always returns an error.
/// This is useful to delay erroring on non-existent files, so that we
/// can do unit testing a driver using non-existing file paths.
class ErrorFile : public File {
ErrorFile(StringRef path, std::error_code ec)
: File(path, kindErrorObject), _ec(ec) {}
std::error_code doParse() override { return _ec; }
const AtomRange<DefinedAtom> defined() const override {
llvm_unreachable("internal error");
const AtomRange<UndefinedAtom> undefined() const override {
llvm_unreachable("internal error");
const AtomRange<SharedLibraryAtom> sharedLibrary() const override {
llvm_unreachable("internal error");
const AtomRange<AbsoluteAtom> absolute() const override {
llvm_unreachable("internal error");
void clearAtoms() override {
std::error_code _ec;
} // end namespace lld