Andrew Scull | 5e1ddfa | 2018-08-14 10:06:54 +0100 | [diff] [blame] | 1 | //===- Core/Resolver.h - Resolves Atom References -------------------------===// |
| 2 | // |
| 3 | // The LLVM Linker |
| 4 | // |
| 5 | // This file is distributed under the University of Illinois Open Source |
| 6 | // License. See LICENSE.TXT for details. |
| 7 | // |
| 8 | //===----------------------------------------------------------------------===// |
| 9 | |
| 10 | #ifndef LLD_CORE_RESOLVER_H |
| 11 | #define LLD_CORE_RESOLVER_H |
| 12 | |
| 13 | #include "lld/Core/ArchiveLibraryFile.h" |
| 14 | #include "lld/Core/File.h" |
| 15 | #include "lld/Core/SharedLibraryFile.h" |
| 16 | #include "lld/Core/Simple.h" |
| 17 | #include "lld/Core/SymbolTable.h" |
| 18 | #include "llvm/ADT/DenseMap.h" |
| 19 | #include "llvm/ADT/DenseSet.h" |
| 20 | #include "llvm/Support/ErrorOr.h" |
| 21 | #include <set> |
| 22 | #include <unordered_map> |
| 23 | #include <unordered_set> |
| 24 | #include <vector> |
| 25 | |
| 26 | namespace lld { |
| 27 | |
| 28 | class Atom; |
| 29 | class LinkingContext; |
| 30 | |
Andrew Scull | cdfcccc | 2018-10-05 20:58:37 +0100 | [diff] [blame^] | 31 | /// The Resolver is responsible for merging all input object files |
Andrew Scull | 5e1ddfa | 2018-08-14 10:06:54 +0100 | [diff] [blame] | 32 | /// and producing a merged graph. |
| 33 | class Resolver { |
| 34 | public: |
| 35 | Resolver(LinkingContext &ctx) : _ctx(ctx), _result(new MergedFile()) {} |
| 36 | |
| 37 | // InputFiles::Handler methods |
| 38 | void doDefinedAtom(OwningAtomPtr<DefinedAtom> atom); |
| 39 | bool doUndefinedAtom(OwningAtomPtr<UndefinedAtom> atom); |
| 40 | void doSharedLibraryAtom(OwningAtomPtr<SharedLibraryAtom> atom); |
| 41 | void doAbsoluteAtom(OwningAtomPtr<AbsoluteAtom> atom); |
| 42 | |
| 43 | // Handle files, this adds atoms from the current file thats |
| 44 | // being processed by the resolver |
| 45 | llvm::Expected<bool> handleFile(File &); |
| 46 | |
| 47 | // Handle an archive library file. |
| 48 | llvm::Expected<bool> handleArchiveFile(File &); |
| 49 | |
| 50 | // Handle a shared library file. |
| 51 | llvm::Error handleSharedLibrary(File &); |
| 52 | |
Andrew Scull | cdfcccc | 2018-10-05 20:58:37 +0100 | [diff] [blame^] | 53 | /// do work of merging and resolving and return list |
Andrew Scull | 5e1ddfa | 2018-08-14 10:06:54 +0100 | [diff] [blame] | 54 | bool resolve(); |
| 55 | |
| 56 | std::unique_ptr<SimpleFile> resultFile() { return std::move(_result); } |
| 57 | |
| 58 | private: |
| 59 | typedef std::function<llvm::Expected<bool>(StringRef)> UndefCallback; |
| 60 | |
| 61 | bool undefinesAdded(int begin, int end); |
| 62 | File *getFile(int &index); |
| 63 | |
Andrew Scull | cdfcccc | 2018-10-05 20:58:37 +0100 | [diff] [blame^] | 64 | /// The main function that iterates over the files to resolve |
Andrew Scull | 5e1ddfa | 2018-08-14 10:06:54 +0100 | [diff] [blame] | 65 | bool resolveUndefines(); |
| 66 | void updateReferences(); |
| 67 | void deadStripOptimize(); |
| 68 | bool checkUndefines(); |
| 69 | void removeCoalescedAwayAtoms(); |
| 70 | llvm::Expected<bool> forEachUndefines(File &file, UndefCallback callback); |
| 71 | |
| 72 | void markLive(const Atom *atom); |
| 73 | |
| 74 | class MergedFile : public SimpleFile { |
| 75 | public: |
| 76 | MergedFile() : SimpleFile("<linker-internal>", kindResolverMergedObject) {} |
| 77 | void addAtoms(llvm::MutableArrayRef<OwningAtomPtr<Atom>> atoms); |
| 78 | }; |
| 79 | |
| 80 | LinkingContext &_ctx; |
| 81 | SymbolTable _symbolTable; |
| 82 | std::vector<OwningAtomPtr<Atom>> _atoms; |
| 83 | std::set<const Atom *> _deadStripRoots; |
| 84 | llvm::DenseSet<const Atom *> _liveAtoms; |
| 85 | llvm::DenseSet<const Atom *> _deadAtoms; |
| 86 | std::unique_ptr<MergedFile> _result; |
| 87 | std::unordered_multimap<const Atom *, const Atom *> _reverseRef; |
| 88 | |
| 89 | // --start-group and --end-group |
| 90 | std::vector<File *> _files; |
| 91 | std::map<File *, bool> _newUndefinesAdded; |
| 92 | |
| 93 | // List of undefined symbols. |
| 94 | std::vector<StringRef> _undefines; |
| 95 | |
| 96 | // Start position in _undefines for each archive/shared library file. |
| 97 | // Symbols from index 0 to the start position are already searched before. |
| 98 | // Searching them again would never succeed. When we look for undefined |
| 99 | // symbols from an archive/shared library file, start from its start |
| 100 | // position to save time. |
| 101 | std::map<File *, size_t> _undefineIndex; |
| 102 | }; |
| 103 | |
| 104 | } // namespace lld |
| 105 | |
| 106 | #endif // LLD_CORE_RESOLVER_H |