1/* Copyright 2021 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/core/ir/utility.h"
17
18#include "mlir/IR/Block.h" // from @llvm-project
19#include "mlir/IR/Operation.h" // from @llvm-project
20#include "mlir/IR/Types.h" // from @llvm-project
21#include "tensorflow/core/ir/dialect.h"
22#include "tensorflow/core/ir/interfaces.h"
23#include "tensorflow/core/ir/types/dialect.h"
24
25namespace mlir {
26namespace tfg {
27
28// For region-based loop ops, the first N block arguments are data values, with
29// N control tokens afterwards.
30Block::BlockArgListType GetLoopRegionDataArgs(Region &region) {
31 Block::BlockArgListType args = region.getArguments();
32 return args.drop_back(args.size() / 2);
33}
34Block::BlockArgListType GetLoopRegionControlTokens(Region &region) {
35 Block::BlockArgListType args = region.getArguments();
36 return args.drop_front(args.size() / 2);
37}
38BlockArgument GetLoopRegionControlOf(BlockArgument data) {
39 Block &block = *data.getOwner();
40 return block.getArgument(data.getArgNumber() + block.getNumArguments() / 2);
41}
42BlockArgument GetLoopRegionDataOf(BlockArgument ctl) {
43 Block &block = *ctl.getOwner();
44 return block.getArgument(ctl.getArgNumber() - block.getNumArguments() / 2);
45}
46
47Value LookupControlDependency(Value data) {
48 assert(!data.getType().isa<ControlType>() && "expected a data type");
49 // If the value is defined by an op, then the last result is the control
50 // dependency.
51 Value control_dep;
52 if (auto result = data.dyn_cast<OpResult>()) {
53 control_dep = *std::prev(result.getOwner()->result_end());
54 } else {
55 auto arg = data.cast<BlockArgument>();
56 control_dep = cast<ControlArgumentInterface>(arg.getOwner()->getParentOp())
57 .getControlTokenOf(arg);
58 }
59 assert(control_dep.getType().isa<ControlType>() && "expected a control type");
60 return control_dep;
61}
62
63Optional<Value> LookupDataValue(Value ctl) {
64 assert(ctl.getType().isa<ControlType>() && "expected a control type");
65 // If the value is defined by an op, then return the first result.
66 Value data;
67 if (auto result = ctl.dyn_cast<OpResult>()) {
68 // If the op only has a control result, then there is no data value.
69 if (result.getOwner()->getNumResults() == 1) return {};
70 data = *result.getOwner()->result_begin();
71 } else {
72 auto arg = ctl.cast<BlockArgument>();
73 data = cast<ControlArgumentInterface>(arg.getOwner()->getParentOp())
74 .getDataValueOf(arg);
75 }
76 assert(!data.getType().isa<ControlType>() && "expected a data type");
77 return data;
78}
79
80} // namespace tfg
81} // namespace mlir
82