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//===- SymbolTable.cpp ----------------------------------------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
#include "SymbolTable.h"
#include "InputFiles.h"
#include "Symbols.h"
#include "lld/Common/ErrorHandler.h"
#include "lld/Common/Memory.h"
using namespace llvm;
using namespace lld;
using namespace lld::macho;
Symbol *SymbolTable::find(StringRef name) {
auto it = symMap.find(llvm::CachedHashStringRef(name));
if (it == symMap.end())
return nullptr;
return symVector[it->second];
}
std::pair<Symbol *, bool> SymbolTable::insert(StringRef name) {
auto p = symMap.insert({CachedHashStringRef(name), (int)symVector.size()});
// Name already present in the symbol table.
if (!p.second)
return {symVector[p.first->second], false};
// Name is a new symbol.
Symbol *sym = reinterpret_cast<Symbol *>(make<SymbolUnion>());
symVector.push_back(sym);
return {sym, true};
}
Symbol *SymbolTable::addDefined(StringRef name, InputSection *isec,
uint32_t value, bool isWeakDef) {
Symbol *s;
bool wasInserted;
bool overridesWeakDef = false;
std::tie(s, wasInserted) = insert(name);
if (!wasInserted) {
if (auto *defined = dyn_cast<Defined>(s)) {
if (isWeakDef)
return s;
if (!defined->isWeakDef())
error("duplicate symbol: " + name);
} else if (auto *dysym = dyn_cast<DylibSymbol>(s)) {
overridesWeakDef = !isWeakDef && dysym->isWeakDef();
}
// Defined symbols take priority over other types of symbols, so in case
// of a name conflict, we fall through to the replaceSymbol() call below.
}
Defined *defined = replaceSymbol<Defined>(s, name, isec, value, isWeakDef,
/*isExternal=*/true);
defined->overridesWeakDef = overridesWeakDef;
return s;
}
Symbol *SymbolTable::addUndefined(StringRef name) {
Symbol *s;
bool wasInserted;
std::tie(s, wasInserted) = insert(name);
if (wasInserted)
replaceSymbol<Undefined>(s, name);
else if (LazySymbol *lazy = dyn_cast<LazySymbol>(s))
lazy->fetchArchiveMember();
return s;
}
Symbol *SymbolTable::addCommon(StringRef name, InputFile *file, uint64_t size,
uint32_t align) {
Symbol *s;
bool wasInserted;
std::tie(s, wasInserted) = insert(name);
if (!wasInserted) {
if (auto *common = dyn_cast<CommonSymbol>(s)) {
if (size < common->size)
return s;
} else if (isa<Defined>(s)) {
return s;
}
// Common symbols take priority over all non-Defined symbols, so in case of
// a name conflict, we fall through to the replaceSymbol() call below.
}
replaceSymbol<CommonSymbol>(s, name, file, size, align);
return s;
}
Symbol *SymbolTable::addDylib(StringRef name, DylibFile *file, bool isWeakDef,
bool isTlv) {
Symbol *s;
bool wasInserted;
std::tie(s, wasInserted) = insert(name);
if (!wasInserted && isWeakDef)
if (auto *defined = dyn_cast<Defined>(s))
if (!defined->isWeakDef())
defined->overridesWeakDef = true;
if (wasInserted || isa<Undefined>(s) ||
(isa<DylibSymbol>(s) && !isWeakDef && s->isWeakDef()))
replaceSymbol<DylibSymbol>(s, file, name, isWeakDef, isTlv);
return s;
}
Symbol *SymbolTable::addLazy(StringRef name, ArchiveFile *file,
const llvm::object::Archive::Symbol &sym) {
Symbol *s;
bool wasInserted;
std::tie(s, wasInserted) = insert(name);
if (wasInserted)
replaceSymbol<LazySymbol>(s, file, sym);
else if (isa<Undefined>(s) || (isa<DylibSymbol>(s) && s->isWeakDef()))
file->fetch(sym);
return s;
}
Symbol *SymbolTable::addDSOHandle(const MachHeaderSection *header) {
Symbol *s;
bool wasInserted;
std::tie(s, wasInserted) = insert(DSOHandle::name);
if (!wasInserted) {
if (auto *defined = dyn_cast<Defined>(s))
error("found defined symbol from " + defined->isec->file->getName() +
" with illegal name " + DSOHandle::name);
}
replaceSymbol<DSOHandle>(s, header);
return s;
}
SymbolTable *macho::symtab;
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