1 //===--- Printable.h - Print function helpers -------------------*- C++ -*-===// 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 // This file defines the Printable struct. 10 // 11 //===----------------------------------------------------------------------===// 12 13 #ifndef LLVM_SUPPORT_PRINTABLE_H 14 #define LLVM_SUPPORT_PRINTABLE_H 15 16 #include <functional> 17 #include <utility> 18 19 namespace llvm { 20 21 class raw_ostream; 22 23 /// Simple wrapper around std::function<void(raw_ostream&)>. 24 /// This class is useful to construct print helpers for raw_ostream. 25 /// 26 /// Example: 27 /// Printable printRegister(unsigned Register) { 28 /// return Printable([Register](raw_ostream &OS) { 29 /// OS << getRegisterName(Register); 30 /// }); 31 /// } 32 /// ... OS << printRegister(Register); ... 33 /// 34 /// Implementation note: Ideally this would just be a typedef, but doing so 35 /// leads to operator << being ambiguous as function has matching constructors 36 /// in some STL versions. I have seen the problem on gcc 4.6 libstdc++ and 37 /// microsoft STL. 38 class Printable { 39 public: 40 std::function<void(raw_ostream &OS)> Print; 41 Printable(std::function<void(raw_ostream &OS)> Print) 42 : Print(std::move(Print)) {} 43 }; 44 45 inline raw_ostream &operator<<(raw_ostream &OS, const Printable &P) { 46 P.Print(OS); 47 return OS; 48 } 49 50 } // namespace llvm 51 52 #endif 53