llvm/lld/COFF/Symbols.h

//===- Symbols.h ------------------------------------------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

#ifndef LLD_COFF_SYMBOLS_H
#define LLD_COFF_SYMBOLS_H

#include "Chunks.h"
#include "Config.h"
#include "lld/Common/LLVM.h"
#include "lld/Common/Memory.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/Object/Archive.h"
#include "llvm/Object/COFF.h"
#include <atomic>
#include <memory>
#include <vector>

namespace lld {

namespace coff {

Archive;
COFFSymbolRef;
coff_import_header;
coff_symbol_generic;

class ArchiveFile;
class COFFLinkerContext;
class InputFile;
class ObjFile;
class SymbolTable;

// The base class for real symbol classes.
class Symbol { … };

// The base class for any defined symbols, including absolute symbols,
// etc.
class Defined : public Symbol { … };

// Symbols defined via a COFF object file or bitcode file.  For COFF files, this
// stores a coff_symbol_generic*, and names of internal symbols are lazily
// loaded through that. For bitcode files, Sym is nullptr and the name is stored
// as a decomposed StringRef.
class DefinedCOFF : public Defined { … };

// Regular defined symbols read from object file symbol tables.
class DefinedRegular : public DefinedCOFF { … };

class DefinedCommon : public DefinedCOFF { … };

// Absolute symbols.
class DefinedAbsolute : public Defined { … };

// This symbol is used for linker-synthesized symbols like __ImageBase and
// __safe_se_handler_table.
class DefinedSynthetic : public Defined { … };

// This class represents a symbol defined in an archive file. It is
// created from an archive file header, and it knows how to load an
// object file from an archive to replace itself with a defined
// symbol. If the resolver finds both Undefined and LazyArchive for
// the same name, it will ask the LazyArchive to load a file.
class LazyArchive : public Symbol { … };

class LazyObject : public Symbol { … };

// MinGW only.
class LazyDLLSymbol : public Symbol { … };

// Undefined symbols.
class Undefined : public Symbol { … };

// Windows-specific classes.

// This class represents a symbol imported from a DLL. This has two
// names for internal use and external use. The former is used for
// name resolution, and the latter is used for the import descriptor
// table in an output. The former has "__imp_" prefix.
class DefinedImportData : public Defined { … };

// This class represents a symbol for a jump table entry which jumps
// to a function in a DLL. Linker are supposed to create such symbols
// without "__imp_" prefix for all function symbols exported from
// DLLs, so that you can call DLL functions as regular functions with
// a regular name. A function pointer is given as a DefinedImportData.
class DefinedImportThunk : public Defined { … };

// If you have a symbol "foo" in your object file, a symbol name
// "__imp_foo" becomes automatically available as a pointer to "foo".
// This class is for such automatically-created symbols.
// Yes, this is an odd feature. We didn't intend to implement that.
// This is here just for compatibility with MSVC.
class DefinedLocalImport : public Defined { … };

inline uint64_t Defined::getRVA() { … }

inline Chunk *Defined::getChunk() { … }

// A buffer class that is large enough to hold any Symbol-derived
// object. We allocate memory using this class and instantiate a symbol
// using the placement new.
SymbolUnion;

template <typename T, typename... ArgT>
void replaceSymbol(Symbol *s, ArgT &&... arg) { … }
} // namespace coff

std::string toString(const coff::COFFLinkerContext &ctx, coff::Symbol &b);
std::string toCOFFString(const coff::COFFLinkerContext &ctx,
                         const llvm::object::Archive::Symbol &b);

} // namespace lld

#endif