1 | /* Copyright 2015 The TensorFlow Authors. All Rights Reserved. |
2 | |
3 | Licensed under the Apache License, Version 2.0 (the "License"); |
4 | you may not use this file except in compliance with the License. |
5 | You may obtain a copy of the License at |
6 | |
7 | http://www.apache.org/licenses/LICENSE-2.0 |
8 | |
9 | Unless required by applicable law or agreed to in writing, software |
10 | distributed under the License is distributed on an "AS IS" BASIS, |
11 | WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
12 | See the License for the specific language governing permissions and |
13 | limitations under the License. |
14 | ==============================================================================*/ |
15 | |
16 | #ifndef TENSORFLOW_CORE_FRAMEWORK_TYPE_INDEX_H_ |
17 | #define TENSORFLOW_CORE_FRAMEWORK_TYPE_INDEX_H_ |
18 | |
19 | #include <string> |
20 | |
21 | #if defined(__GXX_RTTI) || defined(_CPPRTTI) |
22 | #include <typeinfo> |
23 | #endif // __GXX_RTTI |
24 | |
25 | #include "tensorflow/core/platform/hash.h" |
26 | #include "tensorflow/core/platform/types.h" |
27 | |
28 | namespace tensorflow { |
29 | |
30 | // On some platforms, we would like to avoid using RTTI in order to have smaller |
31 | // binary sizes. This file provides a thin TypeIndex class that mimics |
32 | // std::type_index but does not use RTTI (with a minimal set of functions needed |
33 | // by the TensorFlow framework, and more can be added if necessary). In the |
34 | // absence of RTTI, it does not provide the actual name of the type, and only |
35 | // returns a pre-baked string specifying that RTTI is disabled. The hash code |
36 | // provided in this class is unique for each class. However, it is generated at |
37 | // runtime so this hash code should not be serialized - the value for the same |
38 | // type can change from run to run. |
39 | class TypeIndex { |
40 | public: |
41 | TypeIndex(const TypeIndex& src) : hash_(src.hash_), name_(src.name_) {} |
42 | TypeIndex& operator=(const TypeIndex& src) { |
43 | hash_ = src.hash_; |
44 | name_ = src.name_; |
45 | return *this; |
46 | } |
47 | bool operator==(const TypeIndex& rhs) const { return (hash_ == rhs.hash_); } |
48 | bool operator!=(const TypeIndex& rhs) const { return (hash_ != rhs.hash_); } |
49 | ~TypeIndex() {} |
50 | |
51 | const char* name() const { return name_; } |
52 | |
53 | uint64 hash_code() const { return hash_; } |
54 | |
55 | // Returns a TypeIndex object that corresponds to a typename. |
56 | template <typename T> |
57 | static TypeIndex Make() { |
58 | #ifdef PLATFORM_CLOUD_TPU |
59 | static bool hash_bit[1]; |
60 | return TypeIndex(static_cast<uint64>(reinterpret_cast<intptr_t>(hash_bit)), |
61 | typeid(T).name()); |
62 | #endif |
63 | #if defined(__GXX_RTTI) || defined(_CPPRTTI) |
64 | |
65 | // Use a hash based on the type name to avoid issues due to RTLD_LOCAL on |
66 | // MacOS (b/156979412). |
67 | return TypeIndex(Hash64(typeid(T).name()), typeid(T).name()); |
68 | |
69 | #else |
70 | static bool hash_bit[1]; |
71 | #if TARGET_OS_OSX |
72 | // Warn MacOS users that not using RTTI can cause problems (b/156979412). |
73 | #warning \ |
74 | "Compiling with RTTI disabled on MacOS can cause problems when comparing " \ |
75 | "types across shared libraries." |
76 | #endif // TARGET_OS_OSX |
77 | |
78 | // No type names available. |
79 | return TypeIndex(static_cast<uint64>(reinterpret_cast<intptr_t>(hash_bit)), |
80 | "[RTTI disabled]" ); |
81 | #endif // __GXX_RTTI |
82 | } |
83 | |
84 | private: |
85 | // We hide the constructor of the TypeIndex class. Use the templated |
86 | // Make<T>() function to create a TypeIndex object. |
87 | explicit TypeIndex(const uint64 hash, const char* name) |
88 | : hash_(hash), name_(name) {} |
89 | uint64 hash_; |
90 | const char* name_; |
91 | }; |
92 | |
93 | } // namespace tensorflow |
94 | |
95 | #endif // TENSORFLOW_CORE_FRAMEWORK_TYPE_INDEX_H_ |
96 | |