1 /*
2 * Copyright (c) 2013, 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 package jdk.vm.ci.options;
24
25 import java.io.*;
26 import java.util.*;
27 import java.util.Map.Entry;
28
29 /**
30 * An option value.
31 */
32 public class OptionValue<T> {
33 /**
34 * Temporarily changes the value for an option. The {@linkplain OptionValue#getValue() value} of
35 * {@code option} is set to {@code value} until {@link OverrideScope#close()} is called on the
36 * object returned by this method.
37 * <p>
38 * Since the returned object is {@link AutoCloseable} the try-with-resource construct can be
39 * used:
40 *
41 * <pre>
42 * try (OverrideScope s = OptionValue.override(myOption, myValue) {
43 * // code that depends on myOption == myValue
44 * }
45 * </pre>
46 */
47 public static OverrideScope override(OptionValue<?> option, Object value) {
48 OverrideScope current = getOverrideScope();
49 if (current == null) {
50 if (!value.equals(option.getValue())) {
51 return new SingleOverrideScope(option, value);
52 }
53 Map<OptionValue<?>, Object> overrides = Collections.emptyMap();
54 return new MultipleOverridesScope(current, overrides);
55 }
56 return new MultipleOverridesScope(current, option, value);
57 }
58
59 /**
60 * Temporarily changes the values for a set of options. The {@linkplain OptionValue#getValue()
61 * value} of each {@code option} in {@code overrides} is set to the corresponding {@code value}
62 * in {@code overrides} until {@link OverrideScope#close()} is called on the object returned by
63 * this method.
64 * <p>
65 * Since the returned object is {@link AutoCloseable} the try-with-resource construct can be
66 * used:
67 *
68 * <pre>
69 * Map<OptionValue, Object> overrides = new HashMap<>();
70 * overrides.put(myOption1, myValue1);
71 * overrides.put(myOption2, myValue2);
72 * try (OverrideScope s = OptionValue.override(overrides) {
73 * // code that depends on myOption == myValue
74 * }
75 * </pre>
76 */
77 public static OverrideScope override(Map<OptionValue<?>, Object> overrides) {
78 OverrideScope current = getOverrideScope();
79 if (current == null && overrides.size() == 1) {
80 Entry<OptionValue<?>, Object> single = overrides.entrySet().iterator().next();
81 OptionValue<?> option = single.getKey();
82 Object overrideValue = single.getValue();
83 if (!overrideValue.equals(option.getValue())) {
84 return new SingleOverrideScope(option, overrideValue);
85 }
86 }
87 return new MultipleOverridesScope(current, overrides);
88 }
89
90 /**
91 * Temporarily changes the values for a set of options. The {@linkplain OptionValue#getValue()
92 * value} of each {@code option} in {@code overrides} is set to the corresponding {@code value}
93 * in {@code overrides} until {@link OverrideScope#close()} is called on the object returned by
94 * this method.
95 * <p>
96 * Since the returned object is {@link AutoCloseable} the try-with-resource construct can be
97 * used:
98 *
99 * <pre>
100 * try (OverrideScope s = OptionValue.override(myOption1, myValue1, myOption2, myValue2) {
101 * // code that depends on myOption == myValue
102 * }
103 * </pre>
104 *
105 * @param overrides overrides in the form {@code [option1, override1, option2, override2, ...]}
106 */
107 public static OverrideScope override(Object... overrides) {
108 OverrideScope current = getOverrideScope();
109 if (current == null && overrides.length == 2) {
110 OptionValue<?> option = (OptionValue<?>) overrides[0];
111 Object overrideValue = overrides[1];
112 if (!overrideValue.equals(option.getValue())) {
113 return new SingleOverrideScope(option, overrideValue);
114 }
115 }
116 Map<OptionValue<?>, Object> map = Collections.emptyMap();
117 for (int i = 0; i < overrides.length; i += 2) {
118 OptionValue<?> option = (OptionValue<?>) overrides[i];
119 Object overrideValue = overrides[i + 1];
120 if (!overrideValue.equals(option.getValue())) {
121 if (map.isEmpty()) {
122 map = new HashMap<>();
123 }
124 map.put(option, overrideValue);
125 }
126 }
127 return new MultipleOverridesScope(current, map);
128 }
129
130 private static final ThreadLocal<OverrideScope> overrideScopeTL = new ThreadLocal<>();
131
132 protected static OverrideScope getOverrideScope() {
133 return overrideScopeTL.get();
134 }
135
136 protected static void setOverrideScope(OverrideScope overrideScope) {
137 overrideScopeTL.set(overrideScope);
138 }
139
140 private T defaultValue;
141
142 /**
143 * The raw option value.
144 */
145 protected T value;
146
147 private OptionDescriptor descriptor;
148
149 private long reads;
150 private OptionValue<?> next;
151 private static OptionValue<?> head;
152
153 private static final boolean ShowReadsHistogram = Boolean.getBoolean("jvmci.showOptionValueReadsHistogram");
154
155 private static void addToHistogram(OptionValue<?> option) {
156 if (ShowReadsHistogram) {
157 synchronized (OptionValue.class) {
158 option.next = head;
159 head = option;
160 }
161 }
162 }
163
164 @SuppressWarnings("unchecked")
165 public OptionValue(T value) {
166 this.defaultValue = value;
167 this.value = (T) DEFAULT;
168 addToHistogram(this);
169 }
170
171 private static final Object DEFAULT = "DEFAULT";
172 private static final Object UNINITIALIZED = "UNINITIALIZED";
173
174 /**
175 * Creates an uninitialized option value for a subclass that initializes itself
176 * {@link #defaultValue() lazily}.
177 */
178 @SuppressWarnings("unchecked")
179 protected OptionValue() {
180 this.defaultValue = (T) UNINITIALIZED;
181 this.value = (T) DEFAULT;
182 addToHistogram(this);
183 }
184
185 /**
186 * Lazy initialization of default value.
187 */
188 protected T defaultValue() {
189 throw new InternalError("Option without a default value value must override defaultValue()");
190 }
191
192 /**
193 * Sets the descriptor for this option.
194 */
195 public void setDescriptor(OptionDescriptor descriptor) {
196 assert this.descriptor == null : "Overwriting existing descriptor";
197 this.descriptor = descriptor;
198 }
199
200 /**
201 * Returns the descriptor for this option, if it has been set by
202 * {@link #setDescriptor(OptionDescriptor)}.
203 */
204 public OptionDescriptor getDescriptor() {
205 return descriptor;
206 }
207
208 /**
209 * Gets the name of this option. The name for an option value with a null
210 * {@linkplain #setDescriptor(OptionDescriptor) descriptor} is the value of
211 * {@link Object#toString()}.
212 */
213 public String getName() {
214 return descriptor == null ? super.toString() : (descriptor.getDeclaringClass().getName() + "." + descriptor.getName());
215 }
216
217 @Override
218 public String toString() {
219 return getName() + "=" + getValue();
220 }
221
222 /**
223 * The initial value specified in source code. The returned value is not affected by calls to
224 * {@link #setValue(Object)} or registering {@link OverrideScope}s. Therefore, it is also not
225 * affected by options set on the command line.
226 */
227 public T getDefaultValue() {
228 if (defaultValue == UNINITIALIZED) {
229 defaultValue = defaultValue();
230 }
231 return defaultValue;
232 }
233
234 /**
235 * Returns true if the option has the same value that was set in the source code.
236 */
237 public boolean hasDefaultValue() {
238 if (!(this instanceof StableOptionValue)) {
239 getValue(); // ensure initialized
240 }
241 return value == DEFAULT || Objects.equals(value, getDefaultValue());
242 }
243
244 /**
245 * Gets the value of this option.
246 */
247 public T getValue() {
248 if (ShowReadsHistogram) {
249 reads++;
250 }
251 if (!(this instanceof StableOptionValue)) {
252 OverrideScope overrideScope = getOverrideScope();
253 if (overrideScope != null) {
254 T override = overrideScope.getOverride(this);
255 if (override != null) {
256 return override;
257 }
258 }
259 }
260 if (value != DEFAULT) {
261 return value;
262 } else {
263 return getDefaultValue();
264 }
265 }
266
267 /**
268 * Gets the values of this option including overridden values.
269 *
270 * @param c the collection to which the values are added. If null, one is allocated.
271 * @return the collection to which the values were added in order from most overridden to
272 * current value
273 */
274 @SuppressWarnings("unchecked")
275 public Collection<T> getValues(Collection<T> c) {
276 Collection<T> values = c == null ? new ArrayList<>() : c;
277 if (!(this instanceof StableOptionValue)) {
278 OverrideScope overrideScope = getOverrideScope();
279 if (overrideScope != null) {
280 overrideScope.getOverrides(this, (Collection<Object>) values);
281 }
282 }
283 if (value != DEFAULT) {
284 values.add(value);
285 } else {
286 values.add(getDefaultValue());
287 }
288 return values;
289 }
290
291 /**
292 * Sets the value of this option.
293 */
294 @SuppressWarnings("unchecked")
295 public void setValue(Object v) {
296 this.value = (T) v;
297 }
298
299 /**
300 * An object whose {@link #close()} method reverts the option value overriding initiated by
301 * {@link OptionValue#override(OptionValue, Object)} or {@link OptionValue#override(Map)}.
302 */
303 public abstract static class OverrideScope implements AutoCloseable {
304
305 private Map<DerivedOptionValue<?>, Object> derivedCache = null;
306
307 public <T> T getDerived(DerivedOptionValue<T> key) {
308 if (derivedCache == null) {
309 derivedCache = new HashMap<>();
310 }
311 @SuppressWarnings("unchecked")
312 T ret = (T) derivedCache.get(key);
313 if (ret == null) {
314 ret = key.createValue();
315 derivedCache.put(key, ret);
316 }
317 return ret;
318 }
319
320 abstract void addToInherited(Map<OptionValue<?>, Object> inherited);
321
322 abstract <T> T getOverride(OptionValue<T> option);
323
324 abstract void getOverrides(OptionValue<?> option, Collection<Object> c);
325
326 public abstract void close();
327 }
328
329 static class SingleOverrideScope extends OverrideScope {
330
331 private final OptionValue<?> option;
332 private final Object value;
333
334 public SingleOverrideScope(OptionValue<?> option, Object value) {
335 if (option instanceof StableOptionValue) {
336 throw new IllegalArgumentException("Cannot override stable option " + option);
337 }
338 this.option = option;
339 this.value = value;
340 setOverrideScope(this);
341 }
342
343 @Override
344 void addToInherited(Map<OptionValue<?>, Object> inherited) {
345 inherited.put(option, value);
346 }
347
348 @SuppressWarnings("unchecked")
349 @Override
350 <T> T getOverride(OptionValue<T> key) {
351 if (key == this.option) {
352 return (T) value;
353 }
354 return null;
355 }
356
357 @Override
358 void getOverrides(OptionValue<?> key, Collection<Object> c) {
359 if (key == this.option) {
360 c.add(value);
361 }
362 }
363
364 @Override
365 public void close() {
366 setOverrideScope(null);
367 }
368 }
369
370 static class MultipleOverridesScope extends OverrideScope {
371 final OverrideScope parent;
372 final Map<OptionValue<?>, Object> overrides;
373
374 public MultipleOverridesScope(OverrideScope parent, OptionValue<?> option, Object value) {
375 this.parent = parent;
376 this.overrides = new HashMap<>();
377 if (parent != null) {
378 parent.addToInherited(overrides);
379 }
380 if (option instanceof StableOptionValue) {
381 throw new IllegalArgumentException("Cannot override stable option " + option);
382 }
383 if (!value.equals(option.getValue())) {
384 this.overrides.put(option, value);
385 }
386 if (!overrides.isEmpty()) {
387 setOverrideScope(this);
388 }
389 }
390
391 MultipleOverridesScope(OverrideScope parent, Map<OptionValue<?>, Object> overrides) {
392 this.parent = parent;
393 if (overrides.isEmpty() && parent == null) {
394 this.overrides = Collections.emptyMap();
395 return;
396 }
397 this.overrides = new HashMap<>();
398 if (parent != null) {
399 parent.addToInherited(this.overrides);
400 }
401 for (Map.Entry<OptionValue<?>, Object> e : overrides.entrySet()) {
402 OptionValue<?> option = e.getKey();
403 if (option instanceof StableOptionValue) {
404 throw new IllegalArgumentException("Cannot override stable option " + option);
405 }
406 if (!e.getValue().equals(option.getValue())) {
407 this.overrides.put(option, e.getValue());
408 }
409 }
410 if (!this.overrides.isEmpty()) {
411 setOverrideScope(this);
412 }
413 }
414
415 @Override
416 void addToInherited(Map<OptionValue<?>, Object> inherited) {
417 if (parent != null) {
418 parent.addToInherited(inherited);
419 }
420 inherited.putAll(overrides);
421 }
422
423 @SuppressWarnings("unchecked")
424 @Override
425 <T> T getOverride(OptionValue<T> option) {
426 return (T) overrides.get(option);
427 }
428
429 @Override
430 void getOverrides(OptionValue<?> option, Collection<Object> c) {
431 Object v = overrides.get(option);
432 if (v != null) {
433 c.add(v);
434 }
435 if (parent != null) {
436 parent.getOverrides(option, c);
437 }
438 }
439
440 @Override
441 public void close() {
442 if (!overrides.isEmpty()) {
443 setOverrideScope(parent);
444 }
445 }
446 }
447
448 static {
449 if (ShowReadsHistogram) {
450 Runtime.getRuntime().addShutdownHook(new Thread() {
451 @Override
452 public void run() {
453 ArrayList<OptionValue<?>> options = new ArrayList<>();
454 for (OptionValue<?> option = head; option != null; option = option.next) {
455 options.add(option);
456 }
457 Collections.sort(options, new Comparator<OptionValue<?>>() {
458
459 public int compare(OptionValue<?> o1, OptionValue<?> o2) {
460 if (o1.reads < o2.reads) {
461 return -1;
462 } else if (o1.reads > o2.reads) {
463 return 1;
464 } else {
465 return o1.getName().compareTo(o2.getName());
466 }
467 }
468 });
469 PrintStream out = System.out;
470 out.println("=== OptionValue reads histogram ===");
471 for (OptionValue<?> option : options) {
472 out.println(option.reads + "\t" + option);
473 }
474 }
475 });
476 }
477 }
478 }