1 /*
2 * Copyright (C) 2025 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 #include <iostream>
18
19 // Generates constexpr code for intrinsic_utils.h
20 //
21 // To dump the constexpr code to stdout:
22 //
23 // $ clang++ -std=c++2a generate_constexpr_constructible.cpp
24 // $ ./a.out
25 //
26
27 using namespace std;
28
main()29 int main() {
30 const std::string indent(" ");
31 constexpr size_t kElements = 32;
32 // vapply
33 for (size_t i = kElements; i >= 1; --i) {
34 cout << indent << indent;
35 if (i != kElements) cout << "} else ";
36 cout << "if constexpr (is_braces_constructible<VT,\n";
37 for (size_t j = 0; j < i; ) {
38 cout << indent << indent << indent << indent;
39 for (size_t k = 0; k < 8 && j < i; ++k, ++j) {
40 if (k > 0) cout << " ";
41 cout << "any_type";
42 if (j < i - 1) {
43 cout << ",";
44 } else {
45 if (k == 7) {
46 cout << "\n" << indent << indent << indent << indent;
47 }
48 cout << ">()) {";
49 }
50 }
51 cout << "\n";
52 }
53 for (size_t j = 0; j < i; ) {
54 cout << indent << indent << indent;
55 if (j == 0) {
56 cout << "auto& [";
57 } else {
58 cout << indent << indent;
59 }
60 for (size_t k = 0; k < 8 && j < i; ++k, ++j) {
61 if (k > 0) cout << " ";
62 cout << "v" << (j + 1) << (j < i - 1 ? "," : "] = vv;");
63 }
64 cout << "\n";
65 }
66
67 for (size_t j = 0; j < i; ++j) {
68 cout << indent << indent << indent;
69 cout << "vapply(f, v" << (j + 1) << ");\n";
70 }
71 }
72 cout << indent << indent;
73 cout << "} else {\n";
74 cout << indent << indent << indent;
75 cout << "static_assert(false, \"Currently supports up to "
76 << kElements << " members only.\");\n";
77 cout << indent << indent;
78 cout << "}\n";
79 return 0;
80 }
81