1 /*
2  * Copyright (C) 2014 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 #include "post_opt_passes.h"
18 
19 #include "dataflow_iterator-inl.h"
20 
21 namespace art {
22 
Worker(PassDataHolder * data) const23 bool ClearPhiInstructions::Worker(PassDataHolder* data) const {
24   DCHECK(data != nullptr);
25   PassMEDataHolder* pass_me_data_holder = down_cast<PassMEDataHolder*>(data);
26   CompilationUnit* c_unit = pass_me_data_holder->c_unit;
27   DCHECK(c_unit != nullptr);
28   BasicBlock* bb = pass_me_data_holder->bb;
29   DCHECK(bb != nullptr);
30   MIR* mir = bb->first_mir_insn;
31 
32   while (mir != nullptr) {
33     MIR* next = mir->next;
34 
35     Instruction::Code opcode = mir->dalvikInsn.opcode;
36 
37     if (opcode == static_cast<Instruction::Code> (kMirOpPhi)) {
38       bb->RemoveMIR(mir);
39     }
40 
41     mir = next;
42   }
43 
44   // We do not care in reporting a change or not in the MIR.
45   return false;
46 }
47 
Start(PassDataHolder * data) const48 void CalculatePredecessors::Start(PassDataHolder* data) const {
49   DCHECK(data != nullptr);
50   CompilationUnit* c_unit = down_cast<PassMEDataHolder*>(data)->c_unit;
51   DCHECK(c_unit != nullptr);
52   // First get the MIRGraph here to factorize a bit the code.
53   MIRGraph *mir_graph = c_unit->mir_graph.get();
54 
55   // First clear all predecessors.
56   AllNodesIterator first(mir_graph);
57   for (BasicBlock* bb = first.Next(); bb != nullptr; bb = first.Next()) {
58     bb->predecessors.clear();
59   }
60 
61   // Now calculate all predecessors.
62   AllNodesIterator second(mir_graph);
63   for (BasicBlock* bb = second.Next(); bb != nullptr; bb = second.Next()) {
64     // We only care about non hidden blocks.
65     if (bb->hidden == true) {
66       continue;
67     }
68 
69     // Create iterator for visiting children.
70     ChildBlockIterator child_iter(bb, mir_graph);
71 
72     // Now iterate through the children to set the predecessor bits.
73     for (BasicBlock* child = child_iter.Next(); child != nullptr; child = child_iter.Next()) {
74       child->predecessors.push_back(bb->id);
75     }
76   }
77 }
78 
79 }  // namespace art
80