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 "graph_checker.h"
18#include "optimizing_unit_test.h"
19
20namespace art {
21
22/**
23 * Create a simple control-flow graph composed of two blocks:
24 *
25 *   BasicBlock 0, succ: 1
26 *     0: ReturnVoid 1
27 *   BasicBlock 1, pred: 0
28 *     1: Exit
29 */
30HGraph* CreateSimpleCFG(ArenaAllocator* allocator) {
31  HGraph* graph = CreateGraph(allocator);
32  HBasicBlock* entry_block = new (allocator) HBasicBlock(graph);
33  entry_block->AddInstruction(new (allocator) HReturnVoid());
34  graph->AddBlock(entry_block);
35  graph->SetEntryBlock(entry_block);
36  HBasicBlock* exit_block = new (allocator) HBasicBlock(graph);
37  exit_block->AddInstruction(new (allocator) HExit());
38  graph->AddBlock(exit_block);
39  graph->SetExitBlock(exit_block);
40  entry_block->AddSuccessor(exit_block);
41  graph->BuildDominatorTree();
42  return graph;
43}
44
45static void TestCode(const uint16_t* data) {
46  ArenaPool pool;
47  ArenaAllocator allocator(&pool);
48  HGraph* graph = CreateCFG(&allocator, data);
49  ASSERT_NE(graph, nullptr);
50
51  GraphChecker graph_checker(graph);
52  graph_checker.Run();
53  ASSERT_TRUE(graph_checker.IsValid());
54}
55
56class GraphCheckerTest : public CommonCompilerTest {};
57
58TEST_F(GraphCheckerTest, ReturnVoid) {
59  const uint16_t data[] = ZERO_REGISTER_CODE_ITEM(
60      Instruction::RETURN_VOID);
61
62  TestCode(data);
63}
64
65TEST_F(GraphCheckerTest, CFG1) {
66  const uint16_t data[] = ZERO_REGISTER_CODE_ITEM(
67      Instruction::GOTO | 0x100,
68      Instruction::RETURN_VOID);
69
70  TestCode(data);
71}
72
73TEST_F(GraphCheckerTest, CFG2) {
74  const uint16_t data[] = ONE_REGISTER_CODE_ITEM(
75    Instruction::CONST_4 | 0 | 0,
76    Instruction::IF_EQ, 3,
77    Instruction::GOTO | 0x100,
78    Instruction::RETURN_VOID);
79
80  TestCode(data);
81}
82
83TEST_F(GraphCheckerTest, CFG3) {
84  const uint16_t data[] = ONE_REGISTER_CODE_ITEM(
85    Instruction::CONST_4 | 0 | 0,
86    Instruction::IF_EQ, 3,
87    Instruction::GOTO | 0x100,
88    Instruction::GOTO | 0xFF00);
89
90  TestCode(data);
91}
92
93// Test case with an invalid graph containing inconsistent
94// predecessor/successor arcs in CFG.
95TEST_F(GraphCheckerTest, InconsistentPredecessorsAndSuccessors) {
96  ArenaPool pool;
97  ArenaAllocator allocator(&pool);
98
99  HGraph* graph = CreateSimpleCFG(&allocator);
100  GraphChecker graph_checker(graph);
101  graph_checker.Run();
102  ASSERT_TRUE(graph_checker.IsValid());
103
104  // Remove the entry block from the exit block's predecessors, to create an
105  // inconsistent successor/predecessor relation.
106  graph->GetExitBlock()->RemovePredecessor(graph->GetEntryBlock());
107  graph_checker.Run();
108  ASSERT_FALSE(graph_checker.IsValid());
109}
110
111// Test case with an invalid graph containing a non-branch last
112// instruction in a block.
113TEST_F(GraphCheckerTest, BlockEndingWithNonBranchInstruction) {
114  ArenaPool pool;
115  ArenaAllocator allocator(&pool);
116
117  HGraph* graph = CreateSimpleCFG(&allocator);
118  GraphChecker graph_checker(graph);
119  graph_checker.Run();
120  ASSERT_TRUE(graph_checker.IsValid());
121
122  // Remove the sole instruction of the exit block (composed of a
123  // single Exit instruction) to make it invalid (i.e. not ending by a
124  // branch instruction).
125  HBasicBlock* exit_block = graph->GetExitBlock();
126  HInstruction* last_inst = exit_block->GetLastInstruction();
127  exit_block->RemoveInstruction(last_inst);
128
129  graph_checker.Run();
130  ASSERT_FALSE(graph_checker.IsValid());
131}
132
133TEST_F(GraphCheckerTest, SSAPhi) {
134  // This code creates one Phi function during the conversion to SSA form.
135  const uint16_t data[] = ONE_REGISTER_CODE_ITEM(
136    Instruction::CONST_4 | 0 | 0,
137    Instruction::IF_EQ, 3,
138    Instruction::CONST_4 | 4 << 12 | 0,
139    Instruction::RETURN | 0 << 8);
140
141  TestCode(data);
142}
143
144}  // namespace art
145