1 import java.io.*;
2
3 class MergeAllVirts {
4 int a;
5 int b;
6 int c = 100;
7
8 public MergeAllVirts() {}
9 public MergeAllVirts(boolean cond) {
10 if (cond) {
11 this.a = 1;
12 this.b = 20;
13 this.c = 300;
14 blackhole(); // kill locals, so LV0 = this is dead here.
15 } else {
16 this.a = 100;
17 this.b = 50;
18 this.c = 7;
19 blackhole(); // kill locals.
20 }
21 // merge 2 predecessors, but LV0 is not live here.
22 // we need to merge allocation states, or wrong current allocation state is wrong.
23 }
24
25 public int sum() {
26 return a + b + c;
27 }
28
29 public static int add(boolean cond) {
30 MergeAllVirts obj = new MergeAllVirts();
31 if (cond) {
32 obj.a = 1;
33 } else {
34 obj.b = 2;
35 }
36 //obj3 = phi(obj1, obj2);
37 return obj.sum();
38 }
39
40 public static MergeAllVirts cached;
41 public static void escaped(boolean cond) {
42 MergeAllVirts obj = new MergeAllVirts();
43
44 if (cond) {
45 obj.a = 1;
46 } else {
47 obj.b = 2;
48 }
49 // return obj; we don't materialize at exit. if it's virtual, keep it virtual.
50 cached = obj; // materialize here.
51 }
52
53 static void check_result(boolean cond, int sum) {
54 if ((cond && sum != 101) || (!cond && sum != 102)) {
55 throw new RuntimeException("wrong answer: " + sum);
56 }
57 }
58 static void blackhole() {} // not inline this.
59 static void blackhole(MergeAllVirts obj) {} // not inline this.
60 static void blackhole(File file) throws IOException {}
61 public static MergeAllVirts escaped2(boolean cond1, boolean cond2) {
62 MergeAllVirts obj = new MergeAllVirts();
63
64 if (cond1) {
65 obj.a = 20;
66 } else {
67 obj.b = 30;
68 }
69 if (cond2) {
70 blackhole(obj); // materialize obj here.
71 }
72 return obj;
73 }
74
75 static void check_result2(boolean cond1, int sum) {
76 boolean okay = true;
77
78 if (cond1) {
79 okay = sum == 120;
80 } else {
81 okay = sum == 130;
82 }
83
84 if (!okay) {
85 throw new RuntimeException("wrong answer: " + cond1 + " " + sum);
86 }
87 }
88
89 public static MergeAllVirts escaped3(boolean cond1, boolean cond2) {
90 MergeAllVirts obj = new MergeAllVirts();
91
92 if (cond1) {
93 obj.a = 20;
94 } else {
95 obj.b = 30;
96 }
97 if (cond2) {
98 blackhole(obj); // materialize obj here.
99 obj.a = 300;
100 }
101 return obj;
102 }
103
104 static void check_result3(boolean cond1, boolean cond2, int sum) {
105 boolean okay = true;
106
107 if (cond1) {
108 if (cond2)
109 okay = sum == 400; // 300 + 0 + 100
110 else
111 okay = sum == 120;
112 } else {
113 if (cond2)
114 okay = sum == 430; // 300 + 30 + 100
115 else
116 okay = sum == 130;
117 }
118
119 if (!okay) {
120 throw new RuntimeException("wrong answer: " + cond1 + " " + cond2 + " " + sum);
121 }
122 }
123 public static void escaped4(boolean cond) {
124 MergeAllVirts obj = new MergeAllVirts(cond);
125
126 // return obj; we don't materialize at exit. if it's virtual, keep it virtual.
127 cached = obj; // materialize here.
128 }
129
130 static void check_result4(boolean cond, int sum) {
131 boolean okay;
132
133 if (cond) {
134 okay = sum == 321;
135 } else {
136 okay = sum == 157;
137 }
138
139 if (!okay) {
140 throw new RuntimeException("wrong answer: " + cond + " " + sum);
141 }
142 }
143
144 private static void fail(String msg, Object... args) {
145 throw new RuntimeException(msg);
146 }
147
148 // JVM-1880: merge the same object but they have different aliases in its predecessors.
149 // one common reason is exception handler. C2 parse forces to generate a phi for them.
150 // inspired by sun.net.sdp.SdpProvider::<init>
151 public static Object merge_2virts(File file) {
152 MergeAllVirts obj = new MergeAllVirts();
153
154 try {
155 blackhole(file);
156 } catch(IOException e) {
157 // create a phi node : n = phi(region, _, obj)
158 fail("Error reading %s: %s", file, e.getMessage());
159 }
160 // merge here: phi(r, m, n) and n is phi(region, _, obj)
161 // same object but different aliases!
162 return obj;
163 }
164
165 public static MergeAllVirts merge_virts(boolean cond1, boolean cond2) {
166 MergeAllVirts obj = new MergeAllVirts();
167 if (cond1) {
168 if (cond2) {
169 obj.a = 1;
170 } else {
171 obj.a = 2;
172 }
173 blackhole(); // merge obj.a here.
174 } else {
175 obj.b = 20; // merge both obj.a and obj.b
176 }
177 return obj;
178 }
179
180 static void check_result_virts(boolean cond1, boolean cond2, int sum) {
181 boolean okay;
182 if (cond1) {
183 if (cond2) {
184 okay = sum == 101;
185 } else {
186 okay = sum == 102;
187 }
188 } else {
189 okay = sum == 120;
190 }
191
192 if (!okay) {
193 throw new RuntimeException("wrong answer: " + cond1 + " " + cond2 + " " + sum);
194 }
195 }
196
197 public static void main(String[] args) {
198 long iterations = 0;
199 File file = new File("hello");
200 boolean cond2 = true;
201 try {
202 while (true) {
203 boolean cond = 0 == (iterations & 0xf);
204 int sum = MergeAllVirts.add(cond);
205 check_result(cond, sum);
206
207 MergeAllVirts.escaped(cond);
208 check_result(cond, cached.sum());
209
210 cond2 = cond2 ^ cond;
211 sum = MergeAllVirts.escaped2(cond, cond2).sum();
212 check_result2(cond, sum);
213
214 sum = MergeAllVirts.escaped3(cond, cond2).sum();
215 check_result3(cond, cond2, sum);
216
217 MergeAllVirts.escaped4(cond);
218 check_result4(cond, cached.sum());
219
220 MergeAllVirts.merge_2virts(file);
221
222 sum = MergeAllVirts.merge_virts(cond, cond2).sum();
223 check_result_virts(cond, cond2, sum);
224 iterations++;
225 }
226 } finally {
227 System.err.println("Epsilon Test: " + iterations);
228 }
229 }
230 }