1 //===- TensorSpec.h - type descriptor for a tensor --------------*- 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 #ifndef LLVM_ANALYSIS_TENSORSPEC_H
10 #define LLVM_ANALYSIS_TENSORSPEC_H
11 
12 #include "llvm/Config/llvm-config.h"
13 
14 #include "llvm/ADT/StringMap.h"
15 #include "llvm/IR/LLVMContext.h"
16 #include "llvm/Support/JSON.h"
17 
18 #include <memory>
19 #include <optional>
20 #include <vector>
21 
22 namespace llvm {
23 /// TensorSpec encapsulates the specification of a tensor: its dimensions, or
24 /// "shape" (row-major), its type (see TensorSpec::getDataType specializations
25 /// for supported types), its name and port (see "TensorFlow: Large-Scale
26 /// Machine Learning on Heterogeneous Distributed Systems", section 4.2, para 2:
27 /// https://static.googleusercontent.com/media/research.google.com/en//pubs/archive/45166.pdf)
28 ///
29 /// Note that the design is motivated by Tensorflow, but it is not intended to
30 /// be Tensorflow-specific.
31 ///
32 /// Known tensor types. The left part is the C type, the
33 /// right is a name we can use to identify the type (to implement TensorSpec
34 /// equality checks), and to use, if needed, when mapping to an underlying
35 /// evaluator's type system. The main requirement is that the C type we use has
36 /// the same size and encoding (e.g. endian-ness) as the one used by the
37 /// evaluator.
38 #define SUPPORTED_TENSOR_TYPES(M)                                              \
39   M(float, Float)                                                              \
40   M(double, Double)                                                            \
41   M(int8_t, Int8)                                                              \
42   M(uint8_t, UInt8)                                                            \
43   M(int16_t, Int16)                                                            \
44   M(uint16_t, UInt16)                                                          \
45   M(int32_t, Int32)                                                            \
46   M(uint32_t, UInt32)                                                          \
47   M(int64_t, Int64)                                                            \
48   M(uint64_t, UInt64)
49 
50 enum class TensorType {
51   Invalid,
52 #define _TENSOR_TYPE_ENUM_MEMBERS(_, Name) Name,
53   SUPPORTED_TENSOR_TYPES(_TENSOR_TYPE_ENUM_MEMBERS)
54 #undef _TENSOR_TYPE_ENUM_MEMBERS
55       Total
56 };
57 
58 class TensorSpec final {
59 public:
60   template <typename T>
61   static TensorSpec createSpec(const std::string &Name,
62                                const std::vector<int64_t> &Shape,
63                                int Port = 0) {
64     return TensorSpec(Name, Port, getDataType<T>(), sizeof(T), Shape);
65   }
66 
67   const std::string &name() const { return Name; }
68   int port() const { return Port; }
69   TensorType type() const { return Type; }
70   const std::vector<int64_t> &shape() const { return Shape; }
71 
72   bool operator==(const TensorSpec &Other) const {
73     return Name == Other.Name && Port == Other.Port && Type == Other.Type &&
74            Shape == Other.Shape;
75   }
76 
77   bool operator!=(const TensorSpec &Other) const { return !(*this == Other); }
78 
79   /// Get the number of elements in a tensor with this shape.
80   size_t getElementCount() const { return ElementCount; }
81   /// Get the size, in bytes, of one element.
82   size_t getElementByteSize() const { return ElementSize; }
83   /// Get the total size of a memory buffer needed to store the whole tensor.
84   size_t getTotalTensorBufferSize() const { return ElementCount * ElementSize; }
85 
86   template <typename T> bool isElementType() const {
87     return getDataType<T>() == Type;
88   }
89 
90   TensorSpec(const std::string &NewName, const TensorSpec &Other)
91       : TensorSpec(NewName, Other.Port, Other.Type, Other.ElementSize,
92                    Other.Shape) {}
93 
94   void toJSON(json::OStream &OS) const;
95 
96 private:
97   TensorSpec(const std::string &Name, int Port, TensorType Type,
98              size_t ElementSize, const std::vector<int64_t> &Shape);
99 
100   template <typename T> static TensorType getDataType();
101 
102   std::string Name;
103   int Port = 0;
104   TensorType Type = TensorType::Invalid;
105   std::vector<int64_t> Shape;
106   size_t ElementCount = 0;
107   size_t ElementSize = 0;
108 };
109 
110 /// For debugging.
111 std::string tensorValueToString(const char *Buffer, const TensorSpec &Spec);
112 
113 /// Construct a TensorSpec from a JSON dictionary of the form:
114 /// { "name": <string>,
115 ///   "port": <int>,
116 ///   "type": <string. Use LLVM's types, e.g. float, double, int64_t>,
117 ///   "shape": <array of ints> }
118 /// For the "type" field, see the C++ primitive types used in
119 /// TFUTILS_SUPPORTED_TYPES.
120 std::optional<TensorSpec> getTensorSpecFromJSON(LLVMContext &Ctx,
121                                                 const json::Value &Value);
122 
123 #define TFUTILS_GETDATATYPE_DEF(T, Name)                                       \
124   template <> TensorType TensorSpec::getDataType<T>();
125 SUPPORTED_TENSOR_TYPES(TFUTILS_GETDATATYPE_DEF)
126 
127 #undef TFUTILS_GETDATATYPE_DEF
128 } // namespace llvm
129 
130 #endif // LLVM_ANALYSIS_TENSORSPEC_H
131