llvm-project/lld/MachO/SymbolTable.h
Vincent Lee 58edaef3fe [lld-macho] Do not error out on dead stripped duplicate symbols
Builds that error out on duplicate symbols can still succeed if the symbols
will be dead stripped. Currently, this is the current behavior in ld64.
https://github.com/apple-oss-distributions/ld64/blob/main/src/ld/Resolver.cpp#L2018.
In order to provide an easier to path for adoption, introduce a new flag that will
retain compatibility with ld64's behavior (similar to `--deduplicate-literals`). This is
turned off by default since we do not encourage this behavior in the linker.

Reviewed By: #lld-macho, thakis, int3

Differential Revision: https://reviews.llvm.org/D134794
2022-09-30 15:09:27 -07:00

87 lines
2.9 KiB
C++

//===- 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_MACHO_SYMBOL_TABLE_H
#define LLD_MACHO_SYMBOL_TABLE_H
#include "Symbols.h"
#include "lld/Common/LLVM.h"
#include "llvm/ADT/CachedHashString.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/Object/Archive.h"
namespace lld::macho {
class ArchiveFile;
class DylibFile;
class InputFile;
class ObjFile;
class InputSection;
class MachHeaderSection;
class Symbol;
class Defined;
class Undefined;
/*
* Note that the SymbolTable handles name collisions by calling
* replaceSymbol(), which does an in-place update of the Symbol via `placement
* new`. Therefore, there is no need to update any relocations that hold
* pointers the "old" Symbol -- they will automatically point to the new one.
*/
class SymbolTable {
public:
Defined *addDefined(StringRef name, InputFile *, InputSection *,
uint64_t value, uint64_t size, bool isWeakDef,
bool isPrivateExtern, bool isThumb,
bool isReferencedDynamically, bool noDeadStrip,
bool isWeakDefCanBeHidden);
Defined *aliasDefined(Defined *src, StringRef target, InputFile *newFile,
bool makePrivateExtern = false);
Symbol *addUndefined(StringRef name, InputFile *, bool isWeakRef);
Symbol *addCommon(StringRef name, InputFile *, uint64_t size, uint32_t align,
bool isPrivateExtern);
Symbol *addDylib(StringRef name, DylibFile *file, bool isWeakDef, bool isTlv);
Symbol *addDynamicLookup(StringRef name);
Symbol *addLazyArchive(StringRef name, ArchiveFile *file,
const llvm::object::Archive::Symbol &sym);
Symbol *addLazyObject(StringRef name, InputFile &file);
Defined *addSynthetic(StringRef name, InputSection *, uint64_t value,
bool isPrivateExtern, bool includeInSymtab,
bool referencedDynamically);
ArrayRef<Symbol *> getSymbols() const { return symVector; }
Symbol *find(llvm::CachedHashStringRef name);
Symbol *find(StringRef name) { return find(llvm::CachedHashStringRef(name)); }
private:
std::pair<Symbol *, bool> insert(StringRef name, const InputFile *);
llvm::DenseMap<llvm::CachedHashStringRef, int> symMap;
std::vector<Symbol *> symVector;
};
void reportPendingUndefinedSymbols();
void reportPendingDuplicateSymbols();
// Call reportPendingUndefinedSymbols() to emit diagnostics.
void treatUndefinedSymbol(const Undefined &, StringRef source);
void treatUndefinedSymbol(const Undefined &, const InputSection *,
uint64_t offset);
extern std::unique_ptr<SymbolTable> symtab;
} // namespace lld::macho
#endif