llvm-project/lld/COFF/SymbolTable.h

118 lines
3.7 KiB
C++

//===- 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_COFF_SYMBOL_TABLE_H
#define LLD_COFF_SYMBOL_TABLE_H
#include "InputFiles.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/DenseMapInfo.h"
#include "llvm/Support/Allocator.h"
#include "llvm/Support/raw_ostream.h"
namespace llvm {
struct LTOCodeGenerator;
}
namespace lld {
namespace coff {
class Chunk;
class Defined;
class Lazy;
class SymbolBody;
struct Symbol;
// 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().
class SymbolTable {
public:
void addFile(std::unique_ptr<InputFile> File);
std::vector<std::unique_ptr<InputFile>> &getFiles() { return Files; }
void step();
void run();
bool queueEmpty();
// Print an error message on undefined symbols. If Resolve is true, try to
// resolve any undefined symbols and update the symbol table accordingly.
void reportRemainingUndefines(bool Resolve);
// Returns a list of chunks of selected symbols.
std::vector<Chunk *> getChunks();
// Returns a symbol for a given name. Returns a nullptr if not found.
Symbol *find(StringRef Name);
Symbol *findUnderscore(StringRef Name);
// Occasionally we have to resolve an undefined symbol to its
// mangled symbol. This function tries to find a mangled name
// for U from the symbol table, and if found, set the symbol as
// a weak alias for U.
void mangleMaybe(Undefined *U);
StringRef findMangle(StringRef Name);
// Print a layout map to OS.
void printMap(llvm::raw_ostream &OS);
// Build a COFF object representing the combined contents of BitcodeFiles
// and add it to the symbol table. Called after all files are added and
// before the writer writes results to a file.
void addCombinedLTOObject();
// The writer needs to handle DLL import libraries specially in
// order to create the import descriptor table.
std::vector<ImportFile *> ImportFiles;
// The writer needs to infer the machine type from the object files.
std::vector<ObjectFile *> ObjectFiles;
// Creates an Undefined symbol for a given name.
Undefined *addUndefined(StringRef Name);
DefinedRelative *addRelative(StringRef Name, uint64_t VA);
DefinedAbsolute *addAbsolute(StringRef Name, uint64_t VA);
// A list of chunks which to be added to .rdata.
std::vector<Chunk *> LocalImportChunks;
private:
void readArchives();
void readObjects();
void addSymbol(SymbolBody *New);
void addLazy(Lazy *New, std::vector<Symbol *> *Accum);
Symbol *insert(SymbolBody *New);
StringRef findByPrefix(StringRef Prefix);
void addMemberFile(Lazy *Body);
ObjectFile *createLTOObject(llvm::LTOCodeGenerator *CG);
llvm::DenseMap<StringRef, Symbol *> Symtab;
std::vector<std::unique_ptr<InputFile>> Files;
std::vector<ArchiveFile *> ArchiveQueue;
std::vector<InputFile *> ObjectQueue;
std::vector<BitcodeFile *> BitcodeFiles;
std::unique_ptr<MemoryBuffer> LTOMB;
llvm::BumpPtrAllocator Alloc;
};
} // namespace coff
} // namespace lld
#endif