3587de2281
The C++ ABI requires dylibs to pass a pointer to __cxa_atexit which does e.g. cleanup of static global variables. The C++ spec says that the pointer can point to any address in one of the dylib's segments, but in practice ld64 seems to set it to point to the header, so that's what's implemented here. Reviewed By: #lld-macho, smeenai Differential Revision: https://reviews.llvm.org/D83603
111 lines
3.2 KiB
C++
111 lines
3.2 KiB
C++
//===- SymbolTable.cpp ----------------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#include "SymbolTable.h"
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#include "InputFiles.h"
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#include "Symbols.h"
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#include "lld/Common/ErrorHandler.h"
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#include "lld/Common/Memory.h"
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using namespace llvm;
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using namespace lld;
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using namespace lld::macho;
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Symbol *SymbolTable::find(StringRef name) {
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auto it = symMap.find(llvm::CachedHashStringRef(name));
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if (it == symMap.end())
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return nullptr;
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return symVector[it->second];
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}
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std::pair<Symbol *, bool> SymbolTable::insert(StringRef name) {
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auto p = symMap.insert({CachedHashStringRef(name), (int)symVector.size()});
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// Name already present in the symbol table.
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if (!p.second)
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return {symVector[p.first->second], false};
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// Name is a new symbol.
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Symbol *sym = reinterpret_cast<Symbol *>(make<SymbolUnion>());
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symVector.push_back(sym);
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return {sym, true};
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}
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Symbol *SymbolTable::addDefined(StringRef name, InputSection *isec,
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uint32_t value, bool isWeakDef) {
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Symbol *s;
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bool wasInserted;
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std::tie(s, wasInserted) = insert(name);
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if (!wasInserted) {
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if (auto *defined = dyn_cast<Defined>(s)) {
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if (isWeakDef)
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return s;
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if (!defined->isWeakDef())
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error("duplicate symbol: " + name);
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}
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// Defined symbols take priority over other types of symbols, so in case
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// of a name conflict, we fall through to the replaceSymbol() call below.
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}
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replaceSymbol<Defined>(s, name, isec, value, isWeakDef);
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return s;
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}
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Symbol *SymbolTable::addUndefined(StringRef name) {
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Symbol *s;
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bool wasInserted;
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std::tie(s, wasInserted) = insert(name);
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if (wasInserted)
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replaceSymbol<Undefined>(s, name);
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else if (LazySymbol *lazy = dyn_cast<LazySymbol>(s))
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lazy->fetchArchiveMember();
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return s;
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}
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Symbol *SymbolTable::addDylib(StringRef name, DylibFile *file, bool isWeakDef) {
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Symbol *s;
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bool wasInserted;
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std::tie(s, wasInserted) = insert(name);
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if (wasInserted || isa<Undefined>(s) ||
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(isa<DylibSymbol>(s) && !isWeakDef && s->isWeakDef()))
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replaceSymbol<DylibSymbol>(s, file, name, isWeakDef);
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return s;
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}
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Symbol *SymbolTable::addLazy(StringRef name, ArchiveFile *file,
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const llvm::object::Archive::Symbol &sym) {
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Symbol *s;
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bool wasInserted;
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std::tie(s, wasInserted) = insert(name);
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if (wasInserted)
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replaceSymbol<LazySymbol>(s, file, sym);
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else if (isa<Undefined>(s) || (isa<DylibSymbol>(s) && s->isWeakDef()))
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file->fetch(sym);
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return s;
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}
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Symbol *SymbolTable::addDSOHandle(const MachHeaderSection *header) {
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Symbol *s;
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bool wasInserted;
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std::tie(s, wasInserted) = insert(DSOHandle::name);
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if (!wasInserted) {
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if (auto *defined = dyn_cast<Defined>(s))
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error("found defined symbol from " + defined->isec->file->getName() +
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" with illegal name " + DSOHandle::name);
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}
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replaceSymbol<DSOHandle>(s, header);
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return s;
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}
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SymbolTable *macho::symtab;
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