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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_COFF_SYMBOL_TABLE_H
#define LLD_COFF_SYMBOL_TABLE_H
#include "InputFiles.h"
#include "LTO.h"
#include "llvm/ADT/CachedHashString.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/DenseMapInfo.h"
#include "llvm/Support/raw_ostream.h"
namespace llvm {
struct LTOCodeGenerator;
}
namespace lld {
namespace coff {
class Chunk;
class CommonChunk;
class Defined;
class DefinedAbsolute;
class DefinedRelative;
class Lazy;
class SectionChunk;
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 the
// add*() functions, which are called by input files as they are parsed.
// There is one add* function per symbol type.
class SymbolTable {
public:
void addFile(InputFile *File);
// Try to resolve any undefined symbols and update the symbol table
// accordingly, then print an error message for any remaining undefined
// symbols.
void reportRemainingUndefines();
// 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(SymbolBody *B);
StringRef findMangle(StringRef Name);
// Build a set of COFF objects representing the combined contents of
// BitcodeFiles and add them to the symbol table. Called after all files are
// added and before the writer writes results to a file.
void addCombinedLTOObjects();
std::vector<StringRef> compileBitcodeFiles();
// 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.
SymbolBody *addUndefined(StringRef Name);
Symbol *addSynthetic(StringRef N, Chunk *C);
Symbol *addAbsolute(StringRef N, uint64_t VA);
Symbol *addUndefined(StringRef Name, InputFile *F, bool IsWeakAlias);
void addLazy(ArchiveFile *F, const Archive::Symbol Sym);
Symbol *addAbsolute(StringRef N, COFFSymbolRef S);
Symbol *addRegular(InputFile *F, StringRef N, bool IsCOMDAT,
const llvm::object::coff_symbol_generic *S = nullptr,
SectionChunk *C = nullptr);
Symbol *addCommon(InputFile *F, StringRef N, uint64_t Size,
const llvm::object::coff_symbol_generic *S = nullptr,
CommonChunk *C = nullptr);
Symbol *addImportData(StringRef N, ImportFile *F);
Symbol *addImportThunk(StringRef Name, DefinedImportData *S,
uint16_t Machine);
void reportDuplicate(Symbol *Existing, InputFile *NewFile);
// A list of chunks which to be added to .rdata.
std::vector<Chunk *> LocalImportChunks;
private:
std::pair<Symbol *, bool> insert(StringRef Name);
StringRef findByPrefix(StringRef Prefix);
llvm::DenseMap<llvm::CachedHashStringRef, Symbol *> Symtab;
std::vector<BitcodeFile *> BitcodeFiles;
std::unique_ptr<BitcodeCompiler> LTO;
};
extern SymbolTable *Symtab;
} // namespace coff
} // namespace lld
#endif
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