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
19namespace llvm {
20
21class 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.
38class Printable {
39public:
40 std::function<void(raw_ostream &OS)> Print;
41 Printable(std::function<void(raw_ostream &OS)> Print)
42 : Print(std::move(Print)) {}
43};
44
45inline 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