dataflow_iterator-inl.h revision 55fff044d3a4f7196098e25bab1dad106d9b54a2 
1/*
2 * Copyright (C) 2013 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_COMPILER_DEX_DATAFLOW_ITERATOR_INL_H_
18#define ART_COMPILER_DEX_DATAFLOW_ITERATOR_INL_H_
19
20#include "dataflow_iterator.h"
21
22namespace art {
23
24// Single forward pass over the nodes.
25inline BasicBlock* DataflowIterator::ForwardSingleNext() {
26  BasicBlock* res = NULL;
27
28  // Are we not yet at the end?
29  if (idx_ < end_idx_) {
30    // Get the next index.
31    BasicBlockId bb_id = block_id_list_->Get(idx_);
32    res = mir_graph_->GetBasicBlock(bb_id);
33    idx_++;
34  }
35
36  return res;
37}
38
39// Repeat full forward passes over all nodes until no change occurs during a complete pass.
40inline BasicBlock* DataflowIterator::ForwardRepeatNext() {
41  BasicBlock* res = NULL;
42
43  // Are we at the end and have we changed something?
44  if ((idx_ >= end_idx_) && changed_ == true) {
45    // Reset the index.
46    idx_ = start_idx_;
47    repeats_++;
48    changed_ = false;
49  }
50
51  // Are we not yet at the end?
52  if (idx_ < end_idx_) {
53    // Get the BasicBlockId.
54    BasicBlockId bb_id = block_id_list_->Get(idx_);
55    res = mir_graph_->GetBasicBlock(bb_id);
56    idx_++;
57  }
58
59  return res;
60}
61
62// Single reverse pass over the nodes.
63inline BasicBlock* DataflowIterator::ReverseSingleNext() {
64  BasicBlock* res = NULL;
65
66  // Are we not yet at the end?
67  if (idx_ >= 0) {
68    // Get the BasicBlockId.
69    BasicBlockId bb_id = block_id_list_->Get(idx_);
70    res = mir_graph_->GetBasicBlock(bb_id);
71    idx_--;
72  }
73
74  return res;
75}
76
77// Repeat full backwards passes over all nodes until no change occurs during a complete pass.
78inline BasicBlock* DataflowIterator::ReverseRepeatNext() {
79  BasicBlock* res = NULL;
80
81  // Are we done and we changed something during the last iteration?
82  if ((idx_ < 0) && changed_) {
83    // Reset the index.
84    idx_ = start_idx_;
85    repeats_++;
86    changed_ = false;
87  }
88
89  // Are we not yet done?
90  if (idx_ >= 0) {
91    // Get the BasicBlockId.
92    BasicBlockId bb_id = block_id_list_->Get(idx_);
93    res = mir_graph_->GetBasicBlock(bb_id);
94    idx_--;
95  }
96
97  return res;
98}
99
100// AllNodes uses the existing GrowableArray iterator, and should be considered unordered.
101inline BasicBlock* AllNodesIterator::Next(bool had_change) {
102  BasicBlock* res = NULL;
103
104  // Suppose we want to keep looking.
105  bool keep_looking = true;
106
107  // Find the next BasicBlock.
108  while (keep_looking == true) {
109    // Get next BasicBlock.
110    res = all_nodes_iterator_.Next();
111
112    // Are we done or is the BasicBlock not hidden?
113    if ((res == NULL) || (res->hidden == false)) {
114      keep_looking = false;
115    }
116  }
117
118  // Update changed: if had_changed is true, we remember it for the whole iteration.
119  changed_ |= had_change;
120
121  return res;
122}
123
124inline BasicBlock* LoopRepeatingTopologicalSortIterator::Next(bool had_change) {
125  if (idx_ != 0) {
126    // Mark last processed block visited.
127    BasicBlock* bb = mir_graph_->GetBasicBlock(block_id_list_->Get(idx_ - 1));
128    bb->visited = true;
129    if (had_change) {
130      // If we had a change we need to revisit the children.
131      ChildBlockIterator iter(bb, mir_graph_);
132      for (BasicBlock* child_bb = iter.Next(); child_bb != nullptr; child_bb = iter.Next()) {
133        child_bb->visited = false;
134      }
135    }
136  }
137
138  while (true) {
139    // Pop loops we have left and check if we need to recalculate one of them.
140    // NOTE: We need to do this even if idx_ == end_idx_.
141    while (loop_head_stack_->Size() != 0u &&
142        loop_ends_->Get(loop_head_stack_->Peek().first) == idx_) {
143      auto top = loop_head_stack_->Peek();
144      uint16_t loop_head_idx = top.first;
145      bool recalculated = top.second;
146      loop_head_stack_->Pop();
147      BasicBlock* loop_head = mir_graph_->GetBasicBlock(block_id_list_->Get(loop_head_idx));
148      DCHECK(loop_head != nullptr);
149      if (!recalculated || !loop_head->visited) {
150        loop_head_stack_->Insert(std::make_pair(loop_head_idx, true));  // Recalculating this loop.
151        idx_ = loop_head_idx + 1;
152        return loop_head;
153      }
154    }
155
156    if (idx_ == end_idx_) {
157      return nullptr;
158    }
159
160    // Get next block and return it if unvisited.
161    BasicBlockId idx = idx_;
162    idx_ += 1;
163    BasicBlock* bb = mir_graph_->GetBasicBlock(block_id_list_->Get(idx));
164    DCHECK(bb != nullptr);
165    if (!bb->visited) {
166      if (loop_ends_->Get(idx) != 0u) {
167        loop_head_stack_->Insert(std::make_pair(idx, false));  // Not recalculating.
168      }
169      return bb;
170    }
171  }
172}
173
174}  // namespace art
175
176#endif  // ART_COMPILER_DEX_DATAFLOW_ITERATOR_INL_H_
177