Method visitCallBase

lib/indcallsolver/CustomCVPPass.cpp:275–315

Handle call sites. The state of a called function's formal arguments is the merge of the argument state with the call sites corresponding actual argument state. The call site state is the merge of the call site state with the returned value state of the called function.

  /// argument state. The call site state is the merge of the call site state
  /// with the returned value state of the called function.
  void visitCallBase(CallBase &CB,
                     DenseMap<CVPLatticeKey, CVPLatticeVal> &ChangedValues,
                     SparseSolver<CVPLatticeKey, CVPLatticeVal> &SS) {
    Function *F = util::getCalledFunction(CB);
    auto RegI = CVPLatticeKey(&CB, IPOGrouping::Register);

    // If this is an indirect call, save it so we can quickly revisit it when
    // attaching metadata.
    if (!F)
      IndirectCalls.insert(&CB);

    // If we can't track the function's return values, there's nothing to do.
    if (!F || !canTrackReturnsInterprocedurally(F)) {
      // Void return, No need to create and update CVPLattice state as no one
      // can use it.
      if (CB.getType()->isVoidTy())
        return;
      ChangedValues[RegI] = getOverdefinedVal();
      return;
    }

    // Inform the solver that the called function is executable, and perform
    // the merges for the arguments and return value.
    SS.MarkBlockExecutable(&F->front());
    auto RetF = CVPLatticeKey(F, IPOGrouping::Return);
    for (Argument &A : F->args()) {
      auto RegFormal = CVPLatticeKey(&A, IPOGrouping::Register);
      auto RegActual =
          CVPLatticeKey(CB.getArgOperand(A.getArgNo()), IPOGrouping::Register);
      ChangedValues[RegFormal] =
          MergeValues(SS.getValueState(RegFormal), SS.getValueState(RegActual));
    }

    // Void return, No need to create and update CVPLattice state as no one can
    // use it.
    if (CB.getType()->isVoidTy())
      return;

    ChangedValues[RegI] =
        MergeValues(SS.getValueState(RegI), SS.getValueState(RetF));
  }

  /// Handle select instructions. The select instruction state is the merge the
  /// true and false value states.