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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_WASM_SYMBOL_TABLE_H
#define LLD_WASM_SYMBOL_TABLE_H
#include "InputFiles.h"
#include "LTO.h"
#include "Symbols.h"
#include "lld/Common/LLVM.h"
#include "llvm/ADT/CachedHashString.h"
#include "llvm/ADT/DenseSet.h"
namespace lld {
namespace wasm {
class InputSegment;
// 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);
void addCombinedLTOObject();
std::vector<ObjFile *> ObjectFiles;
std::vector<SharedFile *> SharedFiles;
std::vector<BitcodeFile *> BitcodeFiles;
std::vector<InputFunction *> SyntheticFunctions;
std::vector<InputGlobal *> SyntheticGlobals;
void reportRemainingUndefines();
ArrayRef<Symbol *> getSymbols() const { return SymVector; }
Symbol *find(StringRef Name);
void replace(StringRef Name, Symbol* Sym);
void trace(StringRef Name);
Symbol *addDefinedFunction(StringRef Name, uint32_t Flags, InputFile *File,
InputFunction *Function);
Symbol *addDefinedData(StringRef Name, uint32_t Flags, InputFile *File,
InputSegment *Segment, uint32_t Address,
uint32_t Size);
Symbol *addDefinedGlobal(StringRef Name, uint32_t Flags, InputFile *File,
InputGlobal *G);
Symbol *addDefinedEvent(StringRef Name, uint32_t Flags, InputFile *File,
InputEvent *E);
Symbol *addUndefinedFunction(StringRef Name, StringRef ImportName,
StringRef ImportModule, uint32_t Flags,
InputFile *File, const WasmSignature *Signature);
Symbol *addUndefinedData(StringRef Name, uint32_t Flags, InputFile *File);
Symbol *addUndefinedGlobal(StringRef Name, StringRef ImportName,
StringRef ImportModule, uint32_t Flags,
InputFile *File, const WasmGlobalType *Type);
void addLazy(ArchiveFile *F, const llvm::object::Archive::Symbol *Sym);
bool addComdat(StringRef Name);
DefinedData *addSyntheticDataSymbol(StringRef Name, uint32_t Flags);
DefinedGlobal *addSyntheticGlobal(StringRef Name, uint32_t Flags,
InputGlobal *Global);
DefinedFunction *addSyntheticFunction(StringRef Name, uint32_t Flags,
InputFunction *Function);
void handleSymbolVariants();
void handleWeakUndefines();
private:
std::pair<Symbol *, bool> insert(StringRef Name, const InputFile *File);
std::pair<Symbol *, bool> insertName(StringRef Name);
bool getFunctionVariant(Symbol* Sym, const WasmSignature *Sig,
const InputFile *File, Symbol **Out);
InputFunction *replaceWithUnreachable(Symbol *Sym, const WasmSignature &Sig,
StringRef DebugName);
// Maps symbol names to index into the SymVector. -1 means that symbols
// is to not yet in the vector but it should have tracing enabled if it is
// ever added.
llvm::DenseMap<llvm::CachedHashStringRef, int> SymMap;
std::vector<Symbol *> SymVector;
// For certain symbols types, e.g. function symbols, we allow for muliple
// variants of the same symbol with different signatures.
llvm::DenseMap<llvm::CachedHashStringRef, std::vector<Symbol *>> SymVariants;
// 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 set
// is used to uniquify them.
llvm::DenseSet<llvm::CachedHashStringRef> ComdatGroups;
// For LTO.
std::unique_ptr<BitcodeCompiler> LTO;
};
extern SymbolTable *Symtab;
} // namespace wasm
} // namespace lld
#endif