C++ iterator::getParent方法代码示例

bool ReduceCrashingBlocks::TestBlocks(std::vector<const BasicBlock*> &BBs) {
  // Clone the program to try hacking it apart...
  Module *M = CloneModule(BD.getProgram());

  // Convert list to set for fast lookup...
  std::set<BasicBlock*> Blocks;
  for (unsigned i = 0, e = BBs.size(); i != e; ++i) {
    // Convert the basic block from the original module to the new module...
    const Function *F = BBs[i]->getParent();
    Function *CMF = M->getFunction(F->getName());
    assert(CMF && "Function not in module?!");
    assert(CMF->getFunctionType() == F->getFunctionType() && "wrong type?");

    // Get the mapped basic block...
    Function::iterator CBI = CMF->begin();
    std::advance(CBI, std::distance(F->begin(),
                                    Function::const_iterator(BBs[i])));
    Blocks.insert(CBI);
  }

  std::cout << "Checking for crash with only these blocks:";
  unsigned NumPrint = Blocks.size();
  if (NumPrint > 10) NumPrint = 10;
  for (unsigned i = 0, e = NumPrint; i != e; ++i)
    std::cout << " " << BBs[i]->getName();
  if (NumPrint < Blocks.size())
    std::cout << "... <" << Blocks.size() << " total>";
  std::cout << ": ";

  // Loop over and delete any hack up any blocks that are not listed...
  for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I)
    for (Function::iterator BB = I->begin(), E = I->end(); BB != E; ++BB)
      if (!Blocks.count(BB) && BB->getTerminator()->getNumSuccessors()) {
        // Loop over all of the successors of this block, deleting any PHI nodes
        // that might include it.
        for (succ_iterator SI = succ_begin(BB), E = succ_end(BB); SI != E; ++SI)
          (*SI)->removePredecessor(BB);

        if (BB->getTerminator()->getType() != Type::VoidTy)
          BB->getTerminator()->replaceAllUsesWith(
                      Constant::getNullValue(BB->getTerminator()->getType()));

        // Delete the old terminator instruction...
        BB->getInstList().pop_back();

        // Add a new return instruction of the appropriate type...
        const Type *RetTy = BB->getParent()->getReturnType();
        new ReturnInst(RetTy == Type::VoidTy ? 0 :
                       Constant::getNullValue(RetTy), BB);
      }

  // The CFG Simplifier pass may delete one of the basic blocks we are
  // interested in.  If it does we need to take the block out of the list.  Make
  // a "persistent mapping" by turning basic blocks into <function, name> pairs.
  // This won't work well if blocks are unnamed, but that is just the risk we
  // have to take.
  std::vector<std::pair<Function*, std::string> > BlockInfo;

  for (std::set<BasicBlock*>::iterator I = Blocks.begin(), E = Blocks.end();
       I != E; ++I)
    BlockInfo.push_back(std::make_pair((*I)->getParent(), (*I)->getName()));

  // Now run the CFG simplify pass on the function...
  PassManager Passes;
  Passes.add(createCFGSimplificationPass());
  Passes.add(createVerifierPass());
  Passes.run(*M);

  // Try running on the hacked up program...
  if (TestFn(BD, M)) {
    BD.setNewProgram(M);      // It crashed, keep the trimmed version...

    // Make sure to use basic block pointers that point into the now-current
    // module, and that they don't include any deleted blocks.
    BBs.clear();
    for (unsigned i = 0, e = BlockInfo.size(); i != e; ++i) {
      ValueSymbolTable &ST = BlockInfo[i].first->getValueSymbolTable();
      Value* V = ST.lookup(BlockInfo[i].second);
      if (V && V->getType() == Type::LabelTy)
        BBs.push_back(cast<BasicBlock>(V));
    }
    return true;
  }
  delete M;  // It didn't crash, try something else.
  return false;
}