1 /*
2  * Copyright (C) 2015 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 #ifndef ART_RUNTIME_EXPERIMENTAL_FLAGS_H_
18 #define ART_RUNTIME_EXPERIMENTAL_FLAGS_H_
19 
20 #include <ostream>
21 
22 namespace art {
23 
24 // Possible experimental features that might be enabled.
25 struct ExperimentalFlags {
26   // The actual flag values.
27   enum {
28     kNone           = 0x0000,
29     kMethodHandles  = 0x0004,  // 0b00000100
30   };
31 
ExperimentalFlagsExperimentalFlags32   constexpr ExperimentalFlags() : value_(0x0000) {}
ExperimentalFlagsExperimentalFlags33   constexpr ExperimentalFlags(decltype(kNone) t)  // NOLINT [runtime/explicit]
34       : value_(static_cast<uint32_t>(t)) {}
35 
decltypeExperimentalFlags36   constexpr operator decltype(kNone)() const {
37     return static_cast<decltype(kNone)>(value_);
38   }
39 
40   constexpr explicit operator bool() const {
41     return value_ != kNone;
42   }
43 
44   constexpr ExperimentalFlags operator|(const decltype(kNone)& b) const {
45     return static_cast<decltype(kNone)>(value_ | static_cast<uint32_t>(b));
46   }
47   constexpr ExperimentalFlags operator|(const ExperimentalFlags& b) const {
48     return static_cast<decltype(kNone)>(value_ | b.value_);
49   }
50 
51   constexpr ExperimentalFlags operator&(const ExperimentalFlags& b) const {
52     return static_cast<decltype(kNone)>(value_ & b.value_);
53   }
decltypeExperimentalFlags54   constexpr ExperimentalFlags operator&(const decltype(kNone)& b) const {
55     return static_cast<decltype(kNone)>(value_ & static_cast<uint32_t>(b));
56   }
57 
58   constexpr bool operator==(const ExperimentalFlags& b) const {
59     return value_ == b.value_;
60   }
61 
62  private:
63   uint32_t value_;
64 };
65 
66 inline std::ostream& operator<<(std::ostream& stream, const ExperimentalFlags& e) {
67   bool started = false;
68   if (e & ExperimentalFlags::kMethodHandles) {
69     stream << (started ? "|" : "") << "kMethodHandles";
70     started = true;
71   }
72   if (!started) {
73     stream << "kNone";
74   }
75   return stream;
76 }
77 
78 inline std::ostream& operator<<(std::ostream& stream, const decltype(ExperimentalFlags::kNone)& e) {
79   return stream << ExperimentalFlags(e);
80 }
81 
82 }  // namespace art
83 
84 #endif  // ART_RUNTIME_EXPERIMENTAL_FLAGS_H_
85