1 /*
2 * Copyright (c) 2023, 2024, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 */
23
24 package compiler.gcbarriers;
25
26 import compiler.lib.ir_framework.*;
27 import java.lang.invoke.VarHandle;
28 import java.lang.invoke.MethodHandles;
29 import java.util.concurrent.ThreadLocalRandom;
30
31 /**
32 * @test id=Z
33 * @summary Test that the ZGC barrier elision optimization does not elide
34 * necessary barriers. The tests use volatile memory accesses and
35 * blackholes to prevent C2 from simply optimizing them away.
36 * @library /test/lib /
37 * @requires vm.gc.Z
38 * @run driver compiler.gcbarriers.TestZGCBarrierElision test-correctness
39 */
40
41 /**
42 * @test id=ZGen
43 * @summary Test that the ZGC barrier elision optimization elides unnecessary
44 * barriers following simple allocation and domination rules.
45 * @library /test/lib /
46 * @requires vm.gc.Z & (vm.simpleArch == "x64" | vm.simpleArch == "aarch64")
47 * @run driver compiler.gcbarriers.TestZGCBarrierElision test-effectiveness
48 */
49
50 class Inner {}
51
52 class Outer {
53 volatile Inner field1;
54 volatile Inner field2;
55 Outer() {}
56 }
57
58 class Common {
59
60 static Inner inner = new Inner();
61 static Outer outer = new Outer();
62 static Outer outer2 = new Outer();
63 static Outer[] outerArray = new Outer[42];
64
65 static final VarHandle field1VarHandle;
66 static final VarHandle field2VarHandle;
67 static {
68 MethodHandles.Lookup l = MethodHandles.lookup();
69 try {
70 field1VarHandle = l.findVarHandle(Outer.class, "field1", Inner.class);
71 field2VarHandle = l.findVarHandle(Outer.class, "field2", Inner.class);
72 } catch (Exception e) {
73 throw new Error(e);
74 }
75 }
76 static final VarHandle outerArrayVarHandle =
77 MethodHandles.arrayElementVarHandle(Outer[].class);
78
79 static final String REMAINING = "strong";
80 static final String ELIDED = "elided";
81
82 static void blackhole(Object o) {}
83 static void nonInlinedMethod() {}
84 }
85
86 public class TestZGCBarrierElision {
87
88 public static void main(String[] args) {
89 if (args.length != 1) {
90 throw new IllegalArgumentException();
91 }
92 Class testClass;
93 if (args[0].equals("test-correctness")) {
94 testClass = TestZGCCorrectBarrierElision.class;
95 } else if (args[0].equals("test-effectiveness")) {
96 testClass = TestZGCEffectiveBarrierElision.class;
97 } else {
98 throw new IllegalArgumentException();
99 }
100 String commonName = Common.class.getName();
101 TestFramework test = new TestFramework(testClass);
102 test.addFlags("-XX:+UseZGC", "-XX:+UnlockExperimentalVMOptions",
103 "-XX:CompileCommand=blackhole," + commonName + "::blackhole",
104 "-XX:CompileCommand=dontinline," + commonName + "::nonInlinedMethod",
105 "-XX:LoopMaxUnroll=0");
106 test.start();
107 }
108 }
109
110 class TestZGCCorrectBarrierElision {
111
112 @Test
113 @IR(counts = { IRNode.Z_STORE_P_WITH_BARRIER_FLAG, Common.REMAINING, "1" }, phase = CompilePhase.FINAL_CODE)
114 @IR(counts = { IRNode.Z_LOAD_P_WITH_BARRIER_FLAG, Common.REMAINING, "1" }, phase = CompilePhase.FINAL_CODE)
115 static void testLoadThenStore(Outer o, Inner i) {
116 Common.blackhole(o.field1);
117 o.field1 = i;
118 }
119
120 @Test
121 @IR(counts = { IRNode.Z_LOAD_P_WITH_BARRIER_FLAG, Common.REMAINING, "2" }, phase = CompilePhase.FINAL_CODE)
122 static void testLoadThenLoadAnotherField(Outer o) {
123 Common.blackhole(o.field1);
124 Common.blackhole(o.field2);
125 }
126
127 @Test
128 @IR(counts = { IRNode.Z_LOAD_P_WITH_BARRIER_FLAG, Common.REMAINING, "2" }, phase = CompilePhase.FINAL_CODE)
129 static void testLoadThenLoadFromAnotherObject(Outer o1, Outer o2) {
130 Common.blackhole(o1.field1);
131 Common.blackhole(o2.field1);
132 }
133
134 @Run(test = {"testLoadThenStore",
135 "testLoadThenLoadAnotherField",
136 "testLoadThenLoadFromAnotherObject"})
137 void runBasicTests() {
138 testLoadThenStore(Common.outer, Common.inner);
139 testLoadThenLoadAnotherField(Common.outer);
140 testLoadThenLoadFromAnotherObject(Common.outer, Common.outer2);
141 }
142
143 @Test
144 @IR(counts = { IRNode.Z_LOAD_P_WITH_BARRIER_FLAG, Common.REMAINING, "1" }, phase = CompilePhase.FINAL_CODE)
145 @IR(counts = { IRNode.Z_STORE_P_WITH_BARRIER_FLAG, Common.REMAINING, "1" }, phase = CompilePhase.FINAL_CODE)
146 static void testArrayLoadThenStore(Outer[] a, Outer o) {
147 Common.blackhole(Common.outerArrayVarHandle.getVolatile(a, 0));
148 Common.outerArrayVarHandle.setVolatile(a, 0, o);
149 }
150
151 @Test
152 @IR(counts = { IRNode.Z_LOAD_P_WITH_BARRIER_FLAG, Common.REMAINING, "2" }, phase = CompilePhase.FINAL_CODE)
153 static void testArrayLoadThenLoadAnotherElement(Outer[] a) {
154 Common.blackhole(Common.outerArrayVarHandle.getVolatile(a, 0));
155 Common.blackhole(Common.outerArrayVarHandle.getVolatile(a, 10));
156 }
157
158 @Run(test = {"testArrayLoadThenStore",
159 "testArrayLoadThenLoadAnotherElement"})
160 void runArrayTests() {
161 testArrayLoadThenStore(Common.outerArray, Common.outer);
162 testArrayLoadThenLoadAnotherElement(Common.outerArray);
163 }
164
165 @Test
166 @IR(counts = { IRNode.Z_STORE_P_WITH_BARRIER_FLAG, Common.REMAINING, "2" }, phase = CompilePhase.FINAL_CODE)
167 static void testConditionalStoreThenStore(Outer o, Inner i, int value) {
168 if (value % 2 == 0) {
169 o.field1 = i;
170 }
171 o.field1 = i;
172 }
173
174 @Test
175 @IR(counts = { IRNode.Z_STORE_P_WITH_BARRIER_FLAG, Common.REMAINING, "2" }, phase = CompilePhase.FINAL_CODE)
176 static void testStoreThenCallThenStore(Outer o, Inner i) {
177 o.field1 = i;
178 Common.nonInlinedMethod();
179 o.field1 = i;
180 }
181
182 @Run(test = {"testConditionalStoreThenStore",
183 "testStoreThenCallThenStore"})
184 void runControlFlowTests() {
185 testConditionalStoreThenStore(Common.outer, Common.inner, ThreadLocalRandom.current().nextInt(0, 100));
186 testStoreThenCallThenStore(Common.outer, Common.inner);
187 }
188
189 @Test
190 // TODO: 8353182
191 //@IR(counts = { IRNode.Z_GET_AND_SET_P_WITH_BARRIER_FLAG, Common.REMAINING, "1" }, phase = CompilePhase.FINAL_CODE)
192 static void testAllocateThenAtomic(Inner i) {
193 Outer o = new Outer();
194 Common.blackhole(o);
195 Common.field1VarHandle.getAndSet(o, i);
196 }
197
198 @Test
199 // TODO: 8329234
200 //@IR(counts = { IRNode.Z_LOAD_P_WITH_BARRIER_FLAG, Common.REMAINING, "1" }, phase = CompilePhase.FINAL_CODE)
201 // TODO: 8353182
202 //@IR(counts = { IRNode.Z_GET_AND_SET_P_WITH_BARRIER_FLAG, Common.REMAINING, "1" }, phase = CompilePhase.FINAL_CODE)
203 static void testLoadThenAtomic(Outer o, Inner i) {
204 Common.blackhole(o.field1);
205 Common.field1VarHandle.getAndSet(o, i);
206 }
207
208 @Test
209 // TODO: 8353182
210 //@IR(counts = { IRNode.Z_GET_AND_SET_P_WITH_BARRIER_FLAG, Common.REMAINING, "2" }, phase = CompilePhase.FINAL_CODE)
211 static void testAtomicThenAtomicAnotherField(Outer o, Inner i) {
212 Common.field1VarHandle.getAndSet(o, i);
213 Common.field2VarHandle.getAndSet(o, i);
214 }
215
216 @Test
217 // TODO: 8353182
218 //@IR(counts = { IRNode.Z_GET_AND_SET_P_WITH_BARRIER_FLAG, Common.REMAINING, "1" }, phase = CompilePhase.FINAL_CODE)
219 static void testAllocateArrayThenAtomicAtKnownIndex(Outer o) {
220 Outer[] a = new Outer[42];
221 Common.blackhole(a);
222 Common.outerArrayVarHandle.getAndSet(a, 2, o);
223 }
224
225 @Test
226 // TODO: 8353182
227 //@IR(counts = { IRNode.Z_GET_AND_SET_P_WITH_BARRIER_FLAG, Common.REMAINING, "1" }, phase = CompilePhase.FINAL_CODE)
228 static void testAllocateArrayThenAtomicAtUnknownIndex(Outer o, int index) {
229 Outer[] a = new Outer[42];
230 Common.blackhole(a);
231 Common.outerArrayVarHandle.getAndSet(a, index, o);
232 }
233
234 @Test
235 // TODO: 8353182
236 //@IR(counts = { IRNode.Z_GET_AND_SET_P_WITH_BARRIER_FLAG, Common.REMAINING, "2" }, phase = CompilePhase.FINAL_CODE)
237 static void testArrayAtomicThenAtomicAtUnknownIndices(Outer[] a, Outer o, int index1, int index2) {
238 Common.outerArrayVarHandle.getAndSet(a, index1, o);
239 Common.outerArrayVarHandle.getAndSet(a, index2, o);
240 }
241
242 @Run(test = {"testAllocateThenAtomic",
243 "testLoadThenAtomic",
244 "testAtomicThenAtomicAnotherField",
245 "testAllocateArrayThenAtomicAtKnownIndex",
246 "testAllocateArrayThenAtomicAtUnknownIndex",
247 "testArrayAtomicThenAtomicAtUnknownIndices"})
248 void runAtomicOperationTests() {
249 testAllocateThenAtomic(Common.inner);
250 testLoadThenAtomic(Common.outer, Common.inner);
251 testAtomicThenAtomicAnotherField(Common.outer, Common.inner);
252 testAllocateArrayThenAtomicAtKnownIndex(Common.outer);
253 testAllocateArrayThenAtomicAtUnknownIndex(Common.outer, 10);
254 testArrayAtomicThenAtomicAtUnknownIndices(Common.outerArray, Common.outer, 10, 20);
255 }
256 }
257
258 class TestZGCEffectiveBarrierElision {
259
260 @Test
261 @IR(counts = { IRNode.Z_LOAD_P_WITH_BARRIER_FLAG, Common.ELIDED, "1" }, phase = CompilePhase.FINAL_CODE)
262 static void testAllocateThenLoad() {
263 Outer o1 = new Outer();
264 Common.blackhole(o1);
265 // This load is directly optimized away by C2.
266 Common.blackhole(o1.field1);
267 Common.blackhole(o1.field1);
268 }
269
270 @Test
271 @IR(counts = { IRNode.Z_STORE_P_WITH_BARRIER_FLAG, Common.ELIDED, "1" }, phase = CompilePhase.FINAL_CODE)
272 static void testAllocateThenStore(Inner i) {
273 Outer o1 = new Outer();
274 Common.blackhole(o1);
275 o1.field1 = i;
276 }
277
278 @Test
279 @IR(counts = { IRNode.Z_LOAD_P_WITH_BARRIER_FLAG, Common.REMAINING, "1" }, phase = CompilePhase.FINAL_CODE)
280 @IR(counts = { IRNode.Z_LOAD_P_WITH_BARRIER_FLAG, Common.ELIDED, "1" }, phase = CompilePhase.FINAL_CODE)
281 static void testLoadThenLoad(Outer o) {
282 Common.blackhole(o.field1);
283 Common.blackhole(o.field1);
284 }
285
286 @Test
287 @IR(counts = { IRNode.Z_STORE_P_WITH_BARRIER_FLAG, Common.REMAINING, "1" }, phase = CompilePhase.FINAL_CODE)
288 @IR(counts = { IRNode.Z_STORE_P_WITH_BARRIER_FLAG, Common.ELIDED, "1" }, phase = CompilePhase.FINAL_CODE)
289 static void testStoreThenStore(Outer o, Inner i) {
290 o.field1 = i;
291 o.field1 = i;
292 }
293
294 @Test
295 @IR(counts = { IRNode.Z_STORE_P_WITH_BARRIER_FLAG, Common.REMAINING, "1" }, phase = CompilePhase.FINAL_CODE)
296 @IR(counts = { IRNode.Z_LOAD_P_WITH_BARRIER_FLAG, Common.ELIDED, "1" }, phase = CompilePhase.FINAL_CODE)
297 static void testStoreThenLoad(Outer o, Inner i) {
298 o.field1 = i;
299 Common.blackhole(o.field1);
300 }
301
302 @Run(test = {"testAllocateThenLoad",
303 "testAllocateThenStore",
304 "testLoadThenLoad",
305 "testStoreThenStore",
306 "testStoreThenLoad"})
307 void runBasicTests() {
308 testAllocateThenLoad();
309 testAllocateThenStore(Common.inner);
310 testLoadThenLoad(Common.outer);
311 testStoreThenStore(Common.outer, Common.inner);
312 testStoreThenLoad(Common.outer, Common.inner);
313 }
314
315 @Test
316 @IR(counts = { IRNode.Z_STORE_P_WITH_BARRIER_FLAG, Common.ELIDED, "1" }, phase = CompilePhase.FINAL_CODE)
317 static void testAllocateArrayThenStoreAtKnownIndex(Outer o) {
318 Outer[] a = new Outer[42];
319 Common.blackhole(a);
320 Common.outerArrayVarHandle.setVolatile(a, 0, o);
321 }
322
323 @Test
324 @IR(counts = { IRNode.Z_STORE_P_WITH_BARRIER_FLAG, Common.ELIDED, "1" }, phase = CompilePhase.FINAL_CODE)
325 static void testAllocateArrayThenStoreAtUnknownIndex(Outer o, int index) {
326 Outer[] a = new Outer[42];
327 Common.blackhole(a);
328 Common.outerArrayVarHandle.setVolatile(a, index, o);
329 }
330
331 @Test
332 @IR(counts = { IRNode.Z_LOAD_P_WITH_BARRIER_FLAG, Common.REMAINING, "1" }, phase = CompilePhase.FINAL_CODE)
333 @IR(counts = { IRNode.Z_LOAD_P_WITH_BARRIER_FLAG, Common.ELIDED, "1" }, phase = CompilePhase.FINAL_CODE)
334 static void testArrayLoadThenLoad(Outer[] a) {
335 Common.blackhole(Common.outerArrayVarHandle.getVolatile(a, 0));
336 Common.blackhole(Common.outerArrayVarHandle.getVolatile(a, 0));
337 }
338
339 @Test
340 @IR(counts = { IRNode.Z_STORE_P_WITH_BARRIER_FLAG, Common.REMAINING, "1" }, phase = CompilePhase.FINAL_CODE)
341 @IR(counts = { IRNode.Z_STORE_P_WITH_BARRIER_FLAG, Common.ELIDED, "1" }, phase = CompilePhase.FINAL_CODE)
342 static void testArrayStoreThenStore(Outer[] a, Outer o) {
343 Common.outerArrayVarHandle.setVolatile(a, 0, o);
344 Common.outerArrayVarHandle.setVolatile(a, 0, o);
345 }
346
347 @Test
348 @IR(counts = { IRNode.Z_STORE_P_WITH_BARRIER_FLAG, Common.REMAINING, "1" }, phase = CompilePhase.FINAL_CODE)
349 @IR(counts = { IRNode.Z_LOAD_P_WITH_BARRIER_FLAG, Common.ELIDED, "1" }, phase = CompilePhase.FINAL_CODE)
350 static void testArrayStoreThenLoad(Outer[] a, Outer o) {
351 Common.outerArrayVarHandle.setVolatile(a, 0, o);
352 Common.blackhole(Common.outerArrayVarHandle.getVolatile(a, 0));
353 }
354
355 @Run(test = {"testAllocateArrayThenStoreAtKnownIndex",
356 "testAllocateArrayThenStoreAtUnknownIndex",
357 "testArrayLoadThenLoad",
358 "testArrayStoreThenStore",
359 "testArrayStoreThenLoad"})
360 void runArrayTests() {
361 testAllocateArrayThenStoreAtKnownIndex(Common.outer);
362 testAllocateArrayThenStoreAtUnknownIndex(Common.outer, 10);
363 testArrayLoadThenLoad(Common.outerArray);
364 testArrayStoreThenStore(Common.outerArray, Common.outer);
365 testArrayStoreThenLoad(Common.outerArray, Common.outer);
366 }
367
368 @Test
369 @IR(counts = { IRNode.Z_STORE_P_WITH_BARRIER_FLAG, Common.REMAINING, "1" }, phase = CompilePhase.FINAL_CODE)
370 @IR(counts = { IRNode.Z_STORE_P_WITH_BARRIER_FLAG, Common.ELIDED, "1" }, phase = CompilePhase.FINAL_CODE)
371 static void testStoreThenConditionalStore(Outer o, Inner i, int value) {
372 o.field1 = i;
373 if (value % 2 == 0) {
374 o.field1 = i;
375 }
376 }
377
378 @Test
379 @IR(counts = { IRNode.Z_STORE_P_WITH_BARRIER_FLAG, Common.REMAINING, "1" }, phase = CompilePhase.FINAL_CODE)
380 @IR(counts = { IRNode.Z_STORE_P_WITH_BARRIER_FLAG, Common.ELIDED, "1" }, phase = CompilePhase.FINAL_CODE)
381 static void testStoreThenStoreInLoop(Outer o, Inner i) {
382 o.field1 = i;
383 for (int j = 0; j < 100; j++) {
384 o.field1 = i;
385 }
386 }
387
388 @Run(test = {"testStoreThenConditionalStore",
389 "testStoreThenStoreInLoop"})
390 void runControlFlowTests() {
391 testStoreThenConditionalStore(Common.outer, Common.inner, ThreadLocalRandom.current().nextInt(0, 100));
392 testStoreThenStoreInLoop(Common.outer, Common.inner);
393 }
394
395 @Test
396 @IR(counts = { IRNode.Z_STORE_P_WITH_BARRIER_FLAG, Common.REMAINING, "1" }, phase = CompilePhase.FINAL_CODE)
397 // TODO: 8353182
398 //@IR(counts = { IRNode.Z_GET_AND_SET_P_WITH_BARRIER_FLAG, Common.ELIDED, "1" }, phase = CompilePhase.FINAL_CODE)
399 static void testStoreThenAtomic(Outer o, Inner i) {
400 o.field1 = i;
401 Common.field1VarHandle.getAndSet(o, i);
402 }
403
404 @Test
405 // TODO: 8353182
406 //@IR(counts = { IRNode.Z_GET_AND_SET_P_WITH_BARRIER_FLAG, Common.REMAINING, "1" }, phase = CompilePhase.FINAL_CODE)
407 @IR(counts = { IRNode.Z_LOAD_P_WITH_BARRIER_FLAG, Common.ELIDED, "1" }, phase = CompilePhase.FINAL_CODE)
408 static void testAtomicThenLoad(Outer o, Inner i) {
409 Common.field1VarHandle.getAndSet(o, i);
410 Common.blackhole(o.field1);
411 }
412
413 @Test
414 // TODO: 8353182
415 //@IR(counts = { IRNode.Z_GET_AND_SET_P_WITH_BARRIER_FLAG, Common.REMAINING, "1" }, phase = CompilePhase.FINAL_CODE)
416 @IR(counts = { IRNode.Z_STORE_P_WITH_BARRIER_FLAG, Common.ELIDED, "1" }, phase = CompilePhase.FINAL_CODE)
417 static void testAtomicThenStore(Outer o, Inner i) {
418 Common.field1VarHandle.getAndSet(o, i);
419 o.field1 = i;
420 }
421
422 @Test
423 // TODO: 8353182
424 //@IR(counts = { IRNode.Z_GET_AND_SET_P_WITH_BARRIER_FLAG, Common.REMAINING, "1" }, phase = CompilePhase.FINAL_CODE)
425 //@IR(counts = { IRNode.Z_GET_AND_SET_P_WITH_BARRIER_FLAG, Common.ELIDED, "1" }, phase = CompilePhase.FINAL_CODE)
426 static void testAtomicThenAtomic(Outer o, Inner i) {
427 Common.field1VarHandle.getAndSet(o, i);
428 Common.field1VarHandle.getAndSet(o, i);
429 }
430
431 @Test
432 // TODO: 8353182
433 //@IR(counts = { IRNode.Z_GET_AND_SET_P_WITH_BARRIER_FLAG, Common.REMAINING, "1" }, phase = CompilePhase.FINAL_CODE)
434 //@IR(counts = { IRNode.Z_GET_AND_SET_P_WITH_BARRIER_FLAG, Common.ELIDED, "1" }, phase = CompilePhase.FINAL_CODE)
435 static void testArrayAtomicThenAtomic(Outer[] a, Outer o) {
436 Common.outerArrayVarHandle.getAndSet(a, 0, o);
437 Common.outerArrayVarHandle.getAndSet(a, 0, o);
438 }
439
440 @Run(test = {"testStoreThenAtomic",
441 "testAtomicThenLoad",
442 "testAtomicThenStore",
443 "testAtomicThenAtomic",
444 "testArrayAtomicThenAtomic"})
445 void runAtomicOperationTests() {
446 testStoreThenAtomic(Common.outer, Common.inner);
447 testAtomicThenLoad(Common.outer, Common.inner);
448 testAtomicThenStore(Common.outer, Common.inner);
449 testAtomicThenAtomic(Common.outer, Common.inner);
450 testArrayAtomicThenAtomic(Common.outerArray, Common.outer);
451 }
452 }