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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"
#include "llvm/BinaryFormat/WasmTraits.h"
#include <optional>
namespace lld::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:
ArrayRef<Symbol *> symbols() const { return symVector; }
void wrap(Symbol *sym, Symbol *real, Symbol *wrap);
void addFile(InputFile *file);
void compileBitcodeFiles();
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,
InputChunk *segment, uint64_t address, uint64_t size);
Symbol *addDefinedGlobal(StringRef name, uint32_t flags, InputFile *file,
InputGlobal *g);
Symbol *addDefinedTag(StringRef name, uint32_t flags, InputFile *file,
InputTag *t);
Symbol *addDefinedTable(StringRef name, uint32_t flags, InputFile *file,
InputTable *t);
Symbol *addUndefinedFunction(StringRef name,
std::optional<StringRef> importName,
std::optional<StringRef> importModule,
uint32_t flags, InputFile *file,
const WasmSignature *signature,
bool isCalledDirectly);
Symbol *addUndefinedData(StringRef name, uint32_t flags, InputFile *file);
Symbol *addUndefinedGlobal(StringRef name,
std::optional<StringRef> importName,
std::optional<StringRef> importModule,
uint32_t flags, InputFile *file,
const WasmGlobalType *type);
Symbol *addUndefinedTable(StringRef name, std::optional<StringRef> importName,
std::optional<StringRef> importModule,
uint32_t flags, InputFile *file,
const WasmTableType *type);
Symbol *addUndefinedTag(StringRef name, std::optional<StringRef> importName,
std::optional<StringRef> importModule, uint32_t flags,
InputFile *file, const WasmSignature *sig);
TableSymbol *resolveIndirectFunctionTable(bool required);
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);
DefinedData *addOptionalDataSymbol(StringRef name, uint64_t value = 0);
DefinedGlobal *addOptionalGlobalSymbol(StringRef name, InputGlobal *global);
DefinedTable *addSyntheticTable(StringRef name, uint32_t flags,
InputTable *global);
void handleSymbolVariants();
void handleWeakUndefines();
DefinedFunction *createUndefinedStub(const WasmSignature &sig);
std::vector<ObjFile *> objectFiles;
std::vector<StubFile *> stubFiles;
std::vector<SharedFile *> sharedFiles;
std::vector<BitcodeFile *> bitcodeFiles;
std::vector<InputFunction *> syntheticFunctions;
std::vector<InputGlobal *> syntheticGlobals;
std::vector<InputTable *> syntheticTables;
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);
void replaceWithUndefined(Symbol *sym);
TableSymbol *createDefinedIndirectFunctionTable(StringRef name);
TableSymbol *createUndefinedIndirectFunctionTable(StringRef name);
// 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 multiple
// variants of the same symbol with different signatures.
llvm::DenseMap<llvm::CachedHashStringRef, std::vector<Symbol *>> symVariants;
llvm::DenseMap<WasmSignature, DefinedFunction *> stubFunctions;
// 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 lld::wasm
#endif
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