lld/MachO/SymbolTable.cpp

   1 //===- SymbolTable.cpp ----------------------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #include "SymbolTable.h"
  10 #include "InputFiles.h"
  11 #include "Symbols.h"
  12 #include "lld/Common/ErrorHandler.h"
  13 #include "lld/Common/Memory.h"
  14
  15 using namespace llvm;
  16 using namespace lld;
  17 using namespace lld::macho;
  18
  19 Symbol *SymbolTable::find(StringRef name) {
  20   auto it = symMap.find(llvm::CachedHashStringRef(name));
  21   if (it == symMap.end())
  22     return nullptr;
  23   return symVector[it->second];
  24 }
  25
  26 std::pair<Symbol *, bool> SymbolTable::insert(StringRef name) {
  27   auto p = symMap.insert({CachedHashStringRef(name), (int)symVector.size()});
  28
  29   // Name already present in the symbol table.
  30   if (!p.second)
  31     return {symVector[p.first->second], false};
  32
  33   // Name is a new symbol.
  34   Symbol *sym = reinterpret_cast<Symbol *>(make<SymbolUnion>());
  35   symVector.push_back(sym);
  36   return {sym, true};
  37 }
  38
  39 Symbol *SymbolTable::addDefined(StringRef name, InputSection *isec,
  40                                 uint32_t value) {
  41   Symbol *s;
  42   bool wasInserted;
  43   std::tie(s, wasInserted) = insert(name);
  44
  45   if (!wasInserted && isa<Defined>(s))
  46     error("duplicate symbol: " + name);
  47
  48   replaceSymbol<Defined>(s, name, isec, value);
  49   return s;
  50 }
  51
  52 Symbol *SymbolTable::addUndefined(StringRef name) {
  53   Symbol *s;
  54   bool wasInserted;
  55   std::tie(s, wasInserted) = insert(name);
  56
  57   if (wasInserted)
  58     replaceSymbol<Undefined>(s, name);
  59   else if (LazySymbol *lazy = dyn_cast<LazySymbol>(s))
  60     lazy->fetchArchiveMember();
  61   return s;
  62 }
  63
  64 Symbol *SymbolTable::addDylib(StringRef name, DylibFile *file) {
  65   Symbol *s;
  66   bool wasInserted;
  67   std::tie(s, wasInserted) = insert(name);
  68
  69   if (wasInserted || isa<Undefined>(s))
  70     replaceSymbol<DylibSymbol>(s, file, name);
  71   return s;
  72 }
  73
  74 Symbol *SymbolTable::addLazy(StringRef name, ArchiveFile *file,
  75                              const llvm::object::Archive::Symbol &sym) {
  76   Symbol *s;
  77   bool wasInserted;
  78   std::tie(s, wasInserted) = insert(name);
  79
  80   if (wasInserted)
  81     replaceSymbol<LazySymbol>(s, file, sym);
  82   else if (isa<Undefined>(s))
  83     file->fetch(sym);
  84   return s;
  85 }
  86
  87 SymbolTable *macho::symtab;