Beispiel #1
0
void Stub::applyFixup(Relocation& pSrcReloc,
                      IRBuilder& pBuilder,
                      BranchIsland& pIsland) {
  // build a name for stub symbol
  std::string sym_name("__");
  sym_name.append(pSrcReloc.symInfo()->name())
          .append("_")
          .append(name())
          .append("@")
          .append(pIsland.name());

  // create LDSymbol for the stub
  LDSymbol* symbol =
      pBuilder.AddSymbol<IRBuilder::Force, IRBuilder::Unresolve>(
          sym_name,
          ResolveInfo::Function,
          ResolveInfo::Define,
          ResolveInfo::Local,
          size(),
          initSymValue(),
          FragmentRef::Create(*this, initSymValue()),
          ResolveInfo::Default);
  setSymInfo(symbol->resolveInfo());

  // add relocations of this stub (i.e., set the branch target of the stub)
  for (fixup_iterator it = fixup_begin(), ie = fixup_end(); it != ie; ++it) {
    Relocation* reloc =
        Relocation::Create((*it)->type(),
                           *(FragmentRef::Create(*this, (*it)->offset())),
                           (*it)->addend());
    reloc->setSymInfo(pSrcReloc.symInfo());
    pIsland.addRelocation(*reloc);
  }
}
/// create - create a stub if needed, otherwise return NULL
Stub* StubFactory::create(Relocation& pReloc,
                          uint64_t pTargetSymValue,
                          IRBuilder& pBuilder,
                          BranchIslandFactory& pBRIslandFactory)
{
  // find if there is a prototype stub for the input relocation
  Stub* prototype = findPrototype(pReloc,
                                  pReloc.place(),
                                  pTargetSymValue);
  if (NULL != prototype) {
    // find the island for the input relocation
    BranchIsland* island = pBRIslandFactory.find(*(pReloc.targetRef().frag()));
    if (NULL == island) {
      island = pBRIslandFactory.produce(*(pReloc.targetRef().frag()));
    }

    // find if there is such a stub in the island already
    assert(NULL != island);
    Stub* stub = island->findStub(prototype, pReloc);
    if (NULL != stub) {
      // reset the branch target to the stub instead!
      pReloc.setSymInfo(stub->symInfo());
    }
    else {
      // create a stub from the prototype
      stub = prototype->clone();

      // build a name for stub symbol
      std::string name("__");
      name.append(pReloc.symInfo()->name());
      name.append("_");
      name.append(stub->name());
      name.append("@");
      name.append(island->name());

      // create LDSymbol for the stub
      LDSymbol* symbol =
        pBuilder.AddSymbol<IRBuilder::Force, IRBuilder::Resolve>(
                               name,
                               ResolveInfo::Function,
                               ResolveInfo::Define,
                               ResolveInfo::Local,
                               stub->size(), // size
                               stub->initSymValue(), // value
                               FragmentRef::Create(*stub, stub->initSymValue()),
                               ResolveInfo::Default);
      stub->setSymInfo(symbol->resolveInfo());

      // add relocations of this stub (i.e., set the branch target of the stub)
      for (Stub::fixup_iterator it = stub->fixup_begin(),
             ie = stub->fixup_end(); it != ie; ++it) {

        Relocation* reloc = Relocation::Create((*it)->type(),
                                 *(FragmentRef::Create(*stub, (*it)->offset())),
                                 (*it)->addend());
        reloc->setSymInfo(pReloc.symInfo());
        island->addRelocation(*reloc);
      }

      // add stub to the branch island
      island->addStub(prototype, pReloc, *stub);

      // reset the branch target of the input reloc to this stub instead!
      pReloc.setSymInfo(stub->symInfo());
      return stub;
    }
  }
  return NULL;
}