llvm-project/lld/lib/ReaderWriter/ELF/ExecutableAtoms.h

95 lines
3.1 KiB
C++

//===- lib/ReaderWriter/ELF/ExecutableAtoms.h -----------------------------===//
//
// The LLVM Linker
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#ifndef LLD_READER_WRITER_ELF_EXECUTABLE_ATOM_H
#define LLD_READER_WRITER_ELF_EXECUTABLE_ATOM_H
#include "Atoms.h"
#include "File.h"
#include "lld/Core/DefinedAtom.h"
#include "lld/Core/File.h"
#include "lld/Core/Reference.h"
#include "lld/Core/UndefinedAtom.h"
#include "lld/ReaderWriter/Writer.h"
namespace lld {
namespace elf {
/// \brief All atoms are owned by a File. To add linker specific atoms
/// the atoms need to be inserted to a file called (CRuntimeFile) which
/// are basically additional symbols required by libc and other runtime
/// libraries part of executing a program. This class provides support
/// for adding absolute symbols and undefined symbols
template <class ELFT> class CRuntimeFile : public ELFFile<ELFT> {
public:
typedef llvm::object::Elf_Sym_Impl<ELFT> Elf_Sym;
CRuntimeFile(const ELFTargetInfo &ti, StringRef name = "C runtime")
: ELFFile<ELFT>(ti, name) {}
/// \brief add a global absolute atom
virtual void addAbsoluteAtom(StringRef symbolName) {
Elf_Sym *symbol = new (_allocator.Allocate<Elf_Sym>()) Elf_Sym;
symbol->st_name = 0;
symbol->st_value = 0;
symbol->st_shndx = llvm::ELF::SHN_ABS;
symbol->setBindingAndType(llvm::ELF::STB_GLOBAL,
llvm::ELF::STT_OBJECT);
symbol->st_other = llvm::ELF::STV_DEFAULT;
symbol->st_size = 0;
auto *newAtom =
new (_allocator) ELFAbsoluteAtom<ELFT>(*this, symbolName, symbol, -1);
_absoluteAtoms._atoms.push_back(newAtom);
}
/// \brief add an undefined atom
virtual void addUndefinedAtom(StringRef symbolName) {
Elf_Sym *symbol = new (_allocator) Elf_Sym;
symbol->st_name = 0;
symbol->st_value = 0;
symbol->st_shndx = llvm::ELF::SHN_UNDEF;
symbol->st_other = llvm::ELF::STV_DEFAULT;
symbol->st_size = 0;
auto *newAtom =
new (_allocator) ELFUndefinedAtom<ELFT>(*this, symbolName, symbol);
_undefinedAtoms._atoms.push_back(newAtom);
}
virtual const File::atom_collection<DefinedAtom> &defined() const {
return _definedAtoms;
}
virtual const File::atom_collection<UndefinedAtom> &undefined() const {
return _undefinedAtoms;
}
virtual const File::atom_collection<SharedLibraryAtom> &sharedLibrary() const {
return _sharedLibraryAtoms;
}
virtual const File::atom_collection<AbsoluteAtom> &absolute() const {
return _absoluteAtoms;
}
// cannot add atoms to C Runtime file
virtual void addAtom(const Atom &) {
llvm_unreachable("cannot add atoms to Runtime files");
}
protected:
llvm::BumpPtrAllocator _allocator;
File::atom_collection_vector<DefinedAtom> _definedAtoms;
File::atom_collection_vector<UndefinedAtom> _undefinedAtoms;
File::atom_collection_vector<SharedLibraryAtom> _sharedLibraryAtoms;
File::atom_collection_vector<AbsoluteAtom> _absoluteAtoms;
};
} // end namespace elf
} // end namespace lld
#endif