forked from OSchip/llvm-project
104 lines
3.6 KiB
C++
104 lines
3.6 KiB
C++
//===- SymbolTable.h --------------------------------------------*- C++ -*-===//
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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_ELF_SYMBOL_TABLE_H
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#define LLD_ELF_SYMBOL_TABLE_H
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#include "InputFiles.h"
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#include "LTO.h"
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#include "llvm/ADT/MapVector.h"
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namespace lld {
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namespace elf {
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class Lazy;
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template <class ELFT> class OutputSectionBase;
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struct Symbol;
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class Undefined;
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// SymbolTable is a bucket of all known symbols, including defined,
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// undefined, or lazy symbols (the last one is symbols in archive
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// files whose archive members are not yet loaded).
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//
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// We put all symbols of all files to a SymbolTable, and the
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// SymbolTable selects the "best" symbols if there are name
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// conflicts. For example, obviously, a defined symbol is better than
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// an undefined symbol. Or, if there's a conflict between a lazy and a
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// undefined, it'll read an archive member to read a real definition
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// to replace the lazy symbol. The logic is implemented in resolve().
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template <class ELFT> class SymbolTable {
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typedef typename ELFT::Sym Elf_Sym;
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typedef typename ELFT::uint uintX_t;
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public:
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void addFile(std::unique_ptr<InputFile> File);
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void addCombinedLtoObject();
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const llvm::MapVector<StringRef, Symbol *> &getSymbols() const {
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return Symtab;
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}
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const std::vector<std::unique_ptr<ObjectFile<ELFT>>> &getObjectFiles() const {
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return ObjectFiles;
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}
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const std::vector<std::unique_ptr<SharedFile<ELFT>>> &getSharedFiles() const {
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return SharedFiles;
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}
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SymbolBody *addUndefined(StringRef Name);
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SymbolBody *addUndefinedOpt(StringRef Name);
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SymbolBody *addAbsolute(StringRef Name, Elf_Sym &ESym);
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SymbolBody *addSynthetic(StringRef Name, OutputSectionBase<ELFT> &Section,
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uintX_t Value, uint8_t Visibility);
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SymbolBody *addIgnored(StringRef Name);
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void scanShlibUndefined();
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SymbolBody *find(StringRef Name);
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void wrap(StringRef Name);
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InputFile *findFile(SymbolBody *B);
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private:
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Symbol *insert(SymbolBody *New);
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void addLazy(Lazy *New);
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void addMemberFile(Undefined *Undef, Lazy *L);
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void resolve(SymbolBody *Body);
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std::string conflictMsg(SymbolBody *Old, SymbolBody *New);
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// The order the global symbols are in is not defined. We can use an arbitrary
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// order, but it has to be reproducible. That is true even when cross linking.
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// The default hashing of StringRef produces different results on 32 and 64
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// bit systems so we use a MapVector. That is arbitrary, deterministic but
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// a bit inefficient.
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// FIXME: Experiment with passing in a custom hashing or sorting the symbols
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// once symbol resolution is finished.
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llvm::MapVector<StringRef, Symbol *> Symtab;
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llvm::BumpPtrAllocator Alloc;
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// Comdat groups define "link once" sections. If two comdat groups have the
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// same name, only one of them is linked, and the other is ignored. This set
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// is used to uniquify them.
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llvm::DenseSet<StringRef> ComdatGroups;
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// The symbol table owns all file objects.
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std::vector<std::unique_ptr<ArchiveFile>> ArchiveFiles;
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std::vector<std::unique_ptr<ObjectFile<ELFT>>> ObjectFiles;
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std::vector<std::unique_ptr<SharedFile<ELFT>>> SharedFiles;
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std::vector<std::unique_ptr<BitcodeFile>> BitcodeFiles;
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// Set of .so files to not link the same shared object file more than once.
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llvm::DenseSet<StringRef> SoNames;
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std::unique_ptr<BitcodeCompiler> Lto;
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};
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} // namespace elf
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} // namespace lld
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#endif
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