1/* Copyright 2017 The TensorFlow Authors. All Rights Reserved.
2
3Licensed under the Apache License, Version 2.0 (the "License");
4you may not use this file except in compliance with the License.
5You may obtain a copy of the License at
6
7    http://www.apache.org/licenses/LICENSE-2.0
8
9Unless required by applicable law or agreed to in writing, software
10distributed under the License is distributed on an "AS IS" BASIS,
11WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12See the License for the specific language governing permissions and
13limitations under the License.
14==============================================================================*/
15
16#include "tensorflow/compiler/tf2xla/type_util.h"
17#include "tensorflow/compiler/tf2xla/xla_compiler.h"
18#include "tensorflow/compiler/tf2xla/xla_op_kernel.h"
19#include "tensorflow/compiler/tf2xla/xla_op_registry.h"
20#include "tensorflow/core/framework/kernel_def_builder.h"
21#include "tensorflow/core/framework/tensor.pb.h"
22
23namespace tensorflow {
24namespace {
25
26class ConstOp : public XlaOpKernel {
27 public:
28  explicit ConstOp(OpKernelConstruction* ctx) : XlaOpKernel(ctx) {
29    const TensorProto* proto = nullptr;
30    OP_REQUIRES_OK(ctx, ctx->GetAttr("value", &proto));
31    proto_ = *proto;
32    OP_REQUIRES(
33        ctx, ctx->output_type(0) == proto_.dtype(),
34        errors::InvalidArgument("Type mismatch between value (",
35                                DataTypeString(proto_.dtype()), ") and dtype (",
36                                DataTypeString(ctx->output_type(0)), ")"));
37    OP_REQUIRES_OK(ctx, TensorShape::IsValidShape(proto_.tensor_shape()));
38  }
39
40  void Compile(XlaOpKernelContext* ctx) override {
41    TensorShape shape(proto_.tensor_shape());
42
43    if (proto_.dtype() == DT_STRING) {
44      LOG(WARNING) << "Not computing Const of type DT_STRING";
45      ctx->SetInvalidOutput(0);
46      return;
47    }
48    xla::ComputationBuilder* b = ctx->builder();
49
50    // To avoid blowups for large constants filled with the same value,
51    // recognize that case and emit a scalar broadcast instead.
52    if (shape.num_elements() > 1) {
53      switch (proto_.dtype()) {
54        case DT_BOOL:
55          if (proto_.bool_val_size() == 1) {
56            ctx->SetOutput(0,
57                           b->Broadcast(b->ConstantR0<bool>(proto_.bool_val(0)),
58                                        shape.dim_sizes()));
59            return;
60          }
61          break;
62        case DT_FLOAT:
63          if (proto_.float_val_size() == 1) {
64            ctx->SetOutput(
65                0, b->Broadcast(b->ConstantR0<float>(proto_.float_val(0)),
66                                shape.dim_sizes()));
67            return;
68          }
69          break;
70        case DT_DOUBLE:
71          if (proto_.double_val_size() == 1) {
72            ctx->SetOutput(
73                0, b->Broadcast(b->ConstantR0<double>(proto_.double_val(0)),
74                                shape.dim_sizes()));
75            return;
76          }
77          break;
78        case DT_INT32:
79          if (proto_.int_val_size() == 1) {
80            ctx->SetOutput(0,
81                           b->Broadcast(b->ConstantR0<int32>(proto_.int_val(0)),
82                                        shape.dim_sizes()));
83            return;
84          }
85          break;
86        case DT_INT64:
87          if (proto_.int64_val_size() == 1) {
88            ctx->SetOutput(
89                0, b->Broadcast(b->ConstantR0<int64>(proto_.int64_val(0)),
90                                shape.dim_sizes()));
91            return;
92          }
93          break;
94        default:
95          break;
96      }
97    }
98
99    // General case
100    Tensor tensor(proto_.dtype());
101    OP_REQUIRES(ctx, tensor.FromProto(cpu_allocator(), proto_),
102                errors::InvalidArgument("Cannot parse tensor from proto: ",
103                                        proto_.DebugString()));
104    ctx->SetConstantOutput(0, tensor);
105  }
106
107 private:
108  TensorProto proto_;
109  TF_DISALLOW_COPY_AND_ASSIGN(ConstOp);
110};
111
112// XLA_* devices also register a "real" Const operator so we suppress the
113// dummy operator using CompilationOnly().
114REGISTER_XLA_OP(Name("Const").CompilationOnly(), ConstOp);
115
116}  // namespace
117}  // namespace tensorflow
118