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//===- Core/Resolver.h - Resolves Atom References -------------------------===//
//
// The LLVM Linker
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#ifndef LLD_CORE_RESOLVER_H
#define LLD_CORE_RESOLVER_H
#include "lld/Core/ArchiveLibraryFile.h"
#include "lld/Core/File.h"
#include "lld/Core/SharedLibraryFile.h"
#include "lld/Core/Simple.h"
#include "lld/Core/SymbolTable.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/DenseSet.h"
#include "llvm/Support/ErrorOr.h"
#include <set>
#include <unordered_map>
#include <unordered_set>
#include <vector>
namespace lld {
class Atom;
class LinkingContext;
/// The Resolver is responsible for merging all input object files
/// and producing a merged graph.
class Resolver {
public:
Resolver(LinkingContext &ctx) : _ctx(ctx), _result(new MergedFile()) {}
// InputFiles::Handler methods
void doDefinedAtom(OwningAtomPtr<DefinedAtom> atom);
bool doUndefinedAtom(OwningAtomPtr<UndefinedAtom> atom);
void doSharedLibraryAtom(OwningAtomPtr<SharedLibraryAtom> atom);
void doAbsoluteAtom(OwningAtomPtr<AbsoluteAtom> atom);
// Handle files, this adds atoms from the current file thats
// being processed by the resolver
llvm::Expected<bool> handleFile(File &);
// Handle an archive library file.
llvm::Expected<bool> handleArchiveFile(File &);
// Handle a shared library file.
llvm::Error handleSharedLibrary(File &);
/// do work of merging and resolving and return list
bool resolve();
std::unique_ptr<SimpleFile> resultFile() { return std::move(_result); }
private:
typedef std::function<llvm::Expected<bool>(StringRef)> UndefCallback;
bool undefinesAdded(int begin, int end);
File *getFile(int &index);
/// The main function that iterates over the files to resolve
bool resolveUndefines();
void updateReferences();
void deadStripOptimize();
bool checkUndefines();
void removeCoalescedAwayAtoms();
llvm::Expected<bool> forEachUndefines(File &file, UndefCallback callback);
void markLive(const Atom *atom);
class MergedFile : public SimpleFile {
public:
MergedFile() : SimpleFile("<linker-internal>", kindResolverMergedObject) {}
void addAtoms(llvm::MutableArrayRef<OwningAtomPtr<Atom>> atoms);
};
LinkingContext &_ctx;
SymbolTable _symbolTable;
std::vector<OwningAtomPtr<Atom>> _atoms;
std::set<const Atom *> _deadStripRoots;
llvm::DenseSet<const Atom *> _liveAtoms;
llvm::DenseSet<const Atom *> _deadAtoms;
std::unique_ptr<MergedFile> _result;
std::unordered_multimap<const Atom *, const Atom *> _reverseRef;
// --start-group and --end-group
std::vector<File *> _files;
std::map<File *, bool> _newUndefinesAdded;
// List of undefined symbols.
std::vector<StringRef> _undefines;
// Start position in _undefines for each archive/shared library file.
// Symbols from index 0 to the start position are already searched before.
// Searching them again would never succeed. When we look for undefined
// symbols from an archive/shared library file, start from its start
// position to save time.
std::map<File *, size_t> _undefineIndex;
};
} // namespace lld
#endif // LLD_CORE_RESOLVER_H
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