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//===- SymbolTable.h --------------------------------------------*- C++ -*-===//
//
// The LLVM Linker
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#ifndef LLD_ELF_SYMBOL_TABLE_H
#define LLD_ELF_SYMBOL_TABLE_H
#include "InputFiles.h"
#include "llvm/ADT/MapVector.h"
namespace lld {
namespace elf2 {
class Lazy;
template <class ELFT> class OutputSectionBase;
struct Symbol;
class Undefined;
// SymbolTable is a bucket of all known symbols, including defined,
// undefined, or lazy symbols (the last one is symbols in archive
// files whose archive members are not yet loaded).
//
// We put all symbols of all files to a SymbolTable, and the
// SymbolTable selects the "best" symbols if there are name
// conflicts. For example, obviously, a defined symbol is better than
// an undefined symbol. Or, if there's a conflict between a lazy and a
// undefined, it'll read an archive member to read a real definition
// to replace the lazy symbol. The logic is implemented in resolve().
template <class ELFT> class SymbolTable {
public:
SymbolTable();
void addFile(std::unique_ptr<InputFile> File);
const llvm::MapVector<StringRef, Symbol *> &getSymbols() const {
return Symtab;
}
const std::vector<std::unique_ptr<ObjectFile<ELFT>>> &getObjectFiles() const {
return ObjectFiles;
}
const std::vector<std::unique_ptr<SharedFile<ELFT>>> &getSharedFiles() const {
return SharedFiles;
}
SymbolBody *addUndefined(StringRef Name);
SymbolBody *addUndefinedOpt(StringRef Name);
void addAbsolute(StringRef Name,
typename llvm::object::ELFFile<ELFT>::Elf_Sym &ESym);
void addSynthetic(StringRef Name, OutputSectionBase<ELFT> &Section,
typename llvm::object::ELFFile<ELFT>::uintX_t Value);
SymbolBody *addIgnored(StringRef Name);
void scanShlibUndefined();
SymbolBody *find(StringRef Name);
ELFFileBase<ELFT> *findFile(SymbolBody *B);
private:
Symbol *insert(SymbolBody *New);
void addLazy(Lazy *New);
void addMemberFile(Undefined *Undef, Lazy *L);
void resolve(SymbolBody *Body);
std::string conflictMsg(SymbolBody *Old, SymbolBody *New);
std::vector<std::unique_ptr<ArchiveFile>> ArchiveFiles;
// The order the global symbols are in is not defined. We can use an arbitrary
// order, but it has to be reproducible. That is true even when cross linking.
// The default hashing of StringRef produces different results on 32 and 64
// bit systems so we use a MapVector. That is arbitrary, deterministic but
// a bit inefficient.
// FIXME: Experiment with passing in a custom hashing or sorting the symbols
// once symbol resolution is finished.
llvm::MapVector<StringRef, Symbol *> Symtab;
llvm::BumpPtrAllocator Alloc;
llvm::DenseSet<StringRef> Comdats;
// The writer needs to infer the machine type from the object files.
std::vector<std::unique_ptr<ObjectFile<ELFT>>> ObjectFiles;
std::vector<std::unique_ptr<SharedFile<ELFT>>> SharedFiles;
llvm::DenseSet<StringRef> IncludedSoNames;
};
} // namespace elf2
} // namespace lld
#endif
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