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//===- SymbolTable.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_ELF_SYMBOL_TABLE_H
#define LLD_ELF_SYMBOL_TABLE_H
#include "Symbols.h"
#include "llvm/ADT/CachedHashString.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/Support/Compiler.h"
namespace lld::elf {
class InputFile;
class SharedFile;
// 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:
ArrayRef<Symbol *> getSymbols() const { return symVector; }
void wrap(Symbol *sym, Symbol *real, Symbol *wrap);
Symbol *insert(StringRef name);
template <typename T> Symbol *addSymbol(const T &newSym) {
Symbol *sym = insert(newSym.getName());
sym->resolve(newSym);
return sym;
}
Symbol *addAndCheckDuplicate(const Defined &newSym);
void scanVersionScript();
Symbol *find(StringRef name);
void handleDynamicList();
// Set of .so files to not link the same shared object file more than once.
llvm::DenseMap<llvm::CachedHashStringRef, SharedFile *> soNames;
// Comdat groups define "link once" sections. If two comdat groups have the
// same name, only one of them is linked, and the other is ignored. This map
// is used to uniquify them.
llvm::DenseMap<llvm::CachedHashStringRef, const InputFile *> comdatGroups;
private:
SmallVector<Symbol *, 0> findByVersion(SymbolVersion ver);
SmallVector<Symbol *, 0> findAllByVersion(SymbolVersion ver,
bool includeNonDefault);
llvm::StringMap<SmallVector<Symbol *, 0>> &getDemangledSyms();
bool assignExactVersion(SymbolVersion ver, uint16_t versionId,
StringRef versionName, bool includeNonDefault);
void assignWildcardVersion(SymbolVersion ver, uint16_t versionId,
bool includeNonDefault);
// Global symbols and a map from symbol name to the index. The order is not
// defined. We can use an arbitrary order, but it has to be deterministic even
// when cross linking.
llvm::DenseMap<llvm::CachedHashStringRef, int> symMap;
SmallVector<Symbol *, 0> symVector;
// A map from demangled symbol names to their symbol objects.
// This mapping is 1:N because two symbols with different versions
// can have the same name. We use this map to handle "extern C++ {}"
// directive in version scripts.
std::optional<llvm::StringMap<SmallVector<Symbol *, 0>>> demangledSyms;
};
LLVM_LIBRARY_VISIBILITY extern SymbolTable symtab;
} // namespace lld::elf
#endif
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