VMDebug.java revision 2891ca834bd14c4fd6d4351897dd6421ab469f8c 
1/*
2 * Copyright (C) 2007 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
17package dalvik.system;
18
19import java.io.FileDescriptor;
20import java.io.IOException;
21
22/**
23 * Provides access to some VM-specific debug features. Though this class and
24 * many of its members are public, this class is meant to be wrapped in a more
25 * friendly way for use by application developers. On the Android platform, the
26 * recommended way to access this functionality is through the class
27 * <code>android.os.Debug</code>.
28 *
29 * @cts Please complete the spec.
30 *
31 * @hide
32 */
33public final class VMDebug {
34    /**
35     * Specifies the default method trace data file name.
36     *
37     * @deprecated only used in one place, which is unused and deprecated
38     */
39    @Deprecated
40    static public final String DEFAULT_METHOD_TRACE_FILE_NAME = "/sdcard/dmtrace.trace";
41
42    /**
43     * flag for startMethodTracing(), which adds the results from
44     * startAllocCounting to the trace key file.
45     */
46    public static final int TRACE_COUNT_ALLOCS = 1;
47
48    /* constants for getAllocCount */
49    private static final int KIND_ALLOCATED_OBJECTS     = 1<<0;
50    private static final int KIND_ALLOCATED_BYTES       = 1<<1;
51    private static final int KIND_FREED_OBJECTS         = 1<<2;
52    private static final int KIND_FREED_BYTES           = 1<<3;
53    private static final int KIND_GC_INVOCATIONS        = 1<<4;
54    private static final int KIND_CLASS_INIT_COUNT      = 1<<5;
55    private static final int KIND_CLASS_INIT_TIME       = 1<<6;
56    private static final int KIND_EXT_ALLOCATED_OBJECTS = 1<<12;
57    private static final int KIND_EXT_ALLOCATED_BYTES   = 1<<13;
58    private static final int KIND_EXT_FREED_OBJECTS     = 1<<14;
59    private static final int KIND_EXT_FREED_BYTES       = 1<<15;
60
61    public static final int KIND_GLOBAL_ALLOCATED_OBJECTS =
62        KIND_ALLOCATED_OBJECTS;
63    public static final int KIND_GLOBAL_ALLOCATED_BYTES =
64        KIND_ALLOCATED_BYTES;
65    public static final int KIND_GLOBAL_FREED_OBJECTS =
66        KIND_FREED_OBJECTS;
67    public static final int KIND_GLOBAL_FREED_BYTES =
68        KIND_FREED_BYTES;
69    public static final int KIND_GLOBAL_GC_INVOCATIONS =
70        KIND_GC_INVOCATIONS;
71    public static final int KIND_GLOBAL_CLASS_INIT_COUNT =
72        KIND_CLASS_INIT_COUNT;
73    public static final int KIND_GLOBAL_CLASS_INIT_TIME =
74        KIND_CLASS_INIT_TIME;
75    public static final int KIND_GLOBAL_EXT_ALLOCATED_OBJECTS =
76        KIND_EXT_ALLOCATED_OBJECTS;
77    public static final int KIND_GLOBAL_EXT_ALLOCATED_BYTES =
78        KIND_EXT_ALLOCATED_BYTES;
79    public static final int KIND_GLOBAL_EXT_FREED_OBJECTS =
80        KIND_EXT_FREED_OBJECTS;
81    public static final int KIND_GLOBAL_EXT_FREED_BYTES =
82        KIND_EXT_FREED_BYTES;
83
84    public static final int KIND_THREAD_ALLOCATED_OBJECTS =
85        KIND_ALLOCATED_OBJECTS << 16;
86    public static final int KIND_THREAD_ALLOCATED_BYTES =
87        KIND_ALLOCATED_BYTES << 16;
88    public static final int KIND_THREAD_FREED_OBJECTS =
89        KIND_FREED_OBJECTS << 16;
90    public static final int KIND_THREAD_FREED_BYTES =
91        KIND_FREED_BYTES << 16;
92    public static final int KIND_THREAD_GC_INVOCATIONS =
93        KIND_GC_INVOCATIONS << 16;
94    public static final int KIND_THREAD_CLASS_INIT_COUNT =
95        KIND_CLASS_INIT_COUNT << 16;
96    public static final int KIND_THREAD_CLASS_INIT_TIME =
97        KIND_CLASS_INIT_TIME << 16;
98    public static final int KIND_THREAD_EXT_ALLOCATED_OBJECTS =
99        KIND_EXT_ALLOCATED_OBJECTS << 16;
100    public static final int KIND_THREAD_EXT_ALLOCATED_BYTES =
101        KIND_EXT_ALLOCATED_BYTES << 16;
102    public static final int KIND_THREAD_EXT_FREED_OBJECTS =
103        KIND_EXT_FREED_OBJECTS << 16;
104    public static final int KIND_THREAD_EXT_FREED_BYTES =
105        KIND_EXT_FREED_BYTES << 16;
106
107    public static final int KIND_ALL_COUNTS = 0xffffffff;
108
109    /* all methods are static */
110    private VMDebug() {}
111
112    /**
113     * Returns the time since the last known debugger activity.
114     *
115     * @return the time in milliseconds, or -1 if the debugger is not connected
116     */
117    public static native long lastDebuggerActivity();
118
119    /**
120     * Determines if debugging is enabled in this VM.  If debugging is not
121     * enabled, a debugger cannot be attached.
122     *
123     * @return true if debugging is enabled
124     */
125    public static native boolean isDebuggingEnabled();
126
127    /**
128     * Determines if a debugger is currently attached.
129     *
130     * @return true if (and only if) a debugger is connected
131     */
132    public static native boolean isDebuggerConnected();
133
134    /**
135     * Returns an array of strings that identify VM features.  This is
136     * used by DDMS to determine what sorts of operations the VM can
137     * perform.
138     */
139    public static native String[] getVmFeatureList();
140
141    /**
142     * Start method tracing with default name, size, and with <code>0</code>
143     * flags.
144     *
145     * @deprecated not used, not needed
146     */
147    @Deprecated
148    public static void startMethodTracing() {
149        startMethodTracing(DEFAULT_METHOD_TRACE_FILE_NAME, 0, 0);
150    }
151
152    /**
153     * Start method tracing, specifying a file name as well as a default
154     * buffer size. See <a
155     * href="{@docRoot}guide/developing/tools/traceview.html"> Running the
156     * Traceview Debugging Program</a> for information about reading
157     * trace files.
158     *
159     * <p>You can use either a fully qualified path and
160     * name, or just a name. If only a name is specified, the file will
161     * be created under the /sdcard/ directory. If a name is not given,
162     * the default is /sdcard/dmtrace.trace.</p>
163     *
164     * @param traceFileName name to give the trace file
165     * @param bufferSize the maximum size of both files combined. If passed
166     * as <code>0</code>, it defaults to 8MB.
167     * @param flags flags to control method tracing. The only one that
168     * is currently defined is {@link #TRACE_COUNT_ALLOCS}.
169     */
170    public static void startMethodTracing(String traceFileName,
171        int bufferSize, int flags) {
172
173        if (traceFileName == null) {
174            throw new NullPointerException();
175        }
176
177        startMethodTracingNative(traceFileName, null, bufferSize, flags);
178    }
179
180    /**
181     * Like startMethodTracing(String, int, int), but taking an already-opened
182     * FileDescriptor in which the trace is written.  The file name is also
183     * supplied simply for logging.  Makes a dup of the file descriptor.
184     */
185    public static void startMethodTracing(String traceFileName,
186        FileDescriptor fd, int bufferSize, int flags)
187    {
188        if (traceFileName == null || fd == null) {
189            throw new NullPointerException();
190        }
191
192        startMethodTracingNative(traceFileName, fd, bufferSize, flags);
193    }
194
195    /**
196     * Starts method tracing without a backing file.  When stopMethodTracing
197     * is called, the result is sent directly to DDMS.  (If DDMS is not
198     * attached when tracing ends, the profiling data will be discarded.)
199     */
200    public static void startMethodTracingDdms(int bufferSize, int flags) {
201        startMethodTracingNative(null, null, bufferSize, flags);
202    }
203
204    /**
205     * Implements all startMethodTracing variants.
206     */
207    private static native void startMethodTracingNative(String traceFileName,
208        FileDescriptor fd, int bufferSize, int flags);
209
210    /**
211     * Determine whether method tracing is currently active.
212     */
213    public static native boolean isMethodTracingActive();
214
215    /**
216     * Stops method tracing.
217     */
218    public static native void stopMethodTracing();
219
220    /**
221     * Starts sending Dalvik method trace info to the emulator.
222     */
223    public static native void startEmulatorTracing();
224
225    /**
226     * Stops sending Dalvik method trace info to the emulator.
227     */
228    public static native void stopEmulatorTracing();
229
230    /**
231     * Get an indication of thread CPU usage. The value returned indicates the
232     * amount of time that the current thread has spent executing code or
233     * waiting for certain types of I/O.
234     * <p>
235     * The time is expressed in nanoseconds, and is only meaningful when
236     * compared to the result from an earlier call. Note that nanosecond
237     * resolution does not imply nanosecond accuracy.
238     *
239     * @return the CPU usage. A value of -1 means the system does not support
240     *         this feature.
241     */
242    public static native long threadCpuTimeNanos();
243
244    /**
245     * Count the number and aggregate size of memory allocations between
246     * two points.
247     */
248    public static native void startAllocCounting();
249    public static native void stopAllocCounting();
250    public static native int getAllocCount(int kind);
251    public static native void resetAllocCount(int kinds);
252
253    /**
254     * Establishes an object allocation limit in the current thread. Useful for
255     * catching regressions in code that is expected to operate without causing
256     * any allocations. The limit is valid from the return of this method until
257     * it is either changed or the thread terminates.
258     *
259     * @param limit
260     *            the new limit. A value of 0 means not a single new object may
261     *            be allocated. A value of -1 disables the limit.
262     *
263     * @return the previous limit, or -1 if no limit was set
264     *
265     * @see #setGlobalAllocationLimit(int)
266     */
267    public static native int setAllocationLimit(int limit);
268
269    /**
270     * Establishes an object allocation limit for the entire VM. Useful for
271     * catching regressions in code that is expected to operate without causing
272     * any allocations. The limit is valid from the return of this method until
273     * it is either changed or the thread terminates.
274     *
275     * @param limit
276     *            the new limit. A value of 0 means not a single new object may
277     *            be allocated. A value of -1 disables the limit.
278     *
279     * @return the previous limit, or -1 if no limit was set
280     *
281     * @see #setAllocationLimit(int)
282     */
283    public static native int setGlobalAllocationLimit(int limit);
284
285    /**
286     * Count the number of instructions executed between two points.
287     */
288    public static native void startInstructionCounting();
289    public static native void stopInstructionCounting();
290    public static native void getInstructionCount(int[] counts);
291    public static native void resetInstructionCount();
292
293    /**
294     * Dumps a list of loaded class to the log file.
295     */
296    public static native void printLoadedClasses(int flags);
297
298    /**
299     * Gets the number of loaded classes.
300     *
301     * @return the number of loaded classes
302     */
303    public static native int getLoadedClassCount();
304
305    /**
306     * Dumps "hprof" data to the specified file.  This may cause a GC.
307     *
308     * The VM may create a temporary file in the same directory.
309     *
310     * @param fileName Full pathname of output file (e.g. "/sdcard/dump.hprof").
311     * @throws UnsupportedOperationException if the VM was built without
312     *         HPROF support.
313     * @throws IOException if an error occurs while opening or writing files.
314     */
315    public static void dumpHprofData(String fileName) throws IOException {
316        if (fileName == null)
317            throw new NullPointerException();
318        dumpHprofData(fileName, null);
319    }
320
321    /**
322     * Collects "hprof" heap data and sends it to DDMS.  This may cause a GC.
323     *
324     * @throws UnsupportedOperationException if the VM was built without
325     *         HPROF support.
326     */
327    public static native void dumpHprofDataDdms();
328
329    /**
330     * Dumps "hprof" heap data to a file, by name or descriptor.
331     *
332     * @param fileName Name of output file.  If fd is non-null, the
333     *        file name is only used in log messages (and may be null).
334     * @param fd Descriptor of open file that will receive the output.
335     *        If this is null, the fileName is used instead.
336     */
337    public static native void dumpHprofData(String fileName, FileDescriptor fd)
338            throws IOException;
339
340    /**
341     * Primes the register map cache.
342     */
343    public static native boolean cacheRegisterMap(String classAndMethodDesc);
344
345    /**
346     * Dumps the contents of the VM reference tables (e.g. JNI locals and
347     * globals) to the log file.
348     */
349    public static native void dumpReferenceTables();
350
351    /**
352     * Crashes the VM.  Seriously.  Dumps the interpreter stack trace for
353     * the current thread and then aborts the VM so you can see the native
354     * stack trace.  Useful for figuring out how you got somewhere when
355     * lots of native code is involved.
356     */
357    public static native void crash();
358
359    /**
360     * Together with gdb, provide a handy way to stop the VM at user-tagged
361     * locations.
362     */
363    public static native void infopoint(int id);
364
365    /*
366     * Fake method, inserted into dmtrace output when the garbage collector
367     * runs.  Not actually called.
368     */
369    private static void startGC() {}
370
371    /*
372     * Fake method, inserted into dmtrace output during class preparation
373     * (loading and linking, but not verification or initialization).  Not
374     * actually called.
375     */
376    private static void startClassPrep() {}
377
378    /**
379     * Counts the instances of a class.
380     *
381     * @param klass the class to be counted.
382     * @param assignable if false, direct instances of klass are
383     *                   counted.  If true, instances that are
384     *                   assignable to klass, as defined by
385     *                   {@link Class#isAssignableFrom} are counted.
386     * @return the number of matching instances.
387     */
388    public static native long countInstancesOfClass(Class klass, boolean assignable);
389}
390