r = relocs.At(rIdx)

	switch r.Type() {
	case objabi.R_CALL:
		if targType != sym.SDYNIMPORT {
			// nothing to do, the relocation will be laid out in reloc
			return true
		}
		if target.IsExternal() {
			// External linker will do this relocation.
			return true
		}
		// Internal linking, for both ELF and Mach-O.
		// Build a PLT entry and change the relocation target to that entry.

  // external func ops have the trailing underscore.
  std::string external_callee_name = call_op.getCallee().str().append("_");
  TFRFuncOp func = symbol_table_.lookup<TFRFuncOp>(external_callee_name);
  if (!func || !func.isExternal()) return failure();
  // Get the inputs and attributes. The attributes include these from the
  // argument list and also these derived from the inputs.
  SmallVector<Value, 4> inputs;
  NamedAttrList argument_attrs;

		// so we make sure we're pulling in all outer symbols, and their sub
		// symbols. This is not ideal, and these carrier/section symbols could
		// be removed.
		if d.ldr.IsExternal(symIdx) {
			d.mark(d.ldr.OuterSym(symIdx), symIdx)
			d.mark(d.ldr.SubSym(symIdx), symIdx)
		}

		if len(methods) != 0 {
			if !isgotype {
				panic("method found on non-type symbol")
			}

  // because the symbol user map is invalidated once we start deleting while
  // ops.
  for (auto func : module.getOps<func::FuncOp>()) {
    if (func.isExternal()) continue;
    SmallVector<TF::WhileOp> while_callers = GetWhileCallers(func, symbol_map);
    if (while_callers.empty()) continue;
    while_body_func_to_while_ops[func] = while_callers;

    // backtrack through that function call (our analysis will be correct but
    // pessimistic).
    for (CallGraphNode* node : scc) {
      if (node->isExternal()) continue;
      Region* region = node->getCallableRegion();
      GetOrCreateAnalysis(*region);
    }
  }

  // This above call graph analysis will cover all regions attached to functions

			return
		}

		name := ldr.SymName(s)

		// Only windows/386 requires underscore prefix on external symbols.
		if ctxt.Is386() && ctxt.IsExternal() &&
			(t == sym.SHOSTOBJ || t == sym.SUNDEFEXT || ldr.AttrCgoExport(s) ||
				// TODO(cuonglm): remove this hack
				//
				// Previously, windows/386 requires underscore prefix on external symbols,

  assert(operands.empty() && "constant has no operands");

  // Return the held attribute value.
  return getValue();
}

// CallableOpInterface
Region *TFRFuncOp::getCallableRegion() {
  return isExternal() ? nullptr : &getBody().front();
}

//===----------------------------------------------------------------------===//
// Dialect type definitions

  // of constructing the table is offset by the number of queries.
  SymbolTable symbol_table(module);
  for (auto function : module.getOps<FuncOp>()) {
    if (function.isExternal())
      return errors::FailedPrecondition("External functions not supported");

    if (function.getName() == entry_func_id &&
        !configs.export_entry_func_to_flib) {
      entry_func.emplace(function);

  // of constructing the table is offset by the number of queries.
  SymbolTable symbol_table(module);
  for (auto function : module.getOps<FuncOp>()) {
    if (function.isExternal())
      return errors::FailedPrecondition("External functions not supported");

    if (function.getName() == entry_func_id &&
        !configs.export_entry_func_to_flib) {
      entry_func.emplace(function);

  });

  auto& side_effect_analysis = getAnalysis<mlir::TF::SideEffectAnalysis>();
  for (auto func : getOperation().getOps<mlir::func::FuncOp>())
    if (!func.isExternal() &&
        failed(FormClustersInFunction(
            func, side_effect_analysis.GetAnalysisForFunc(func),
            strict_clusters_)))
      return signalPassFailure();
}
}  // anonymous namespace