v8  4.2.77(io.js2.5.0)
V8 is Google's open source JavaScript engine
v8-profiler.h
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1 // Copyright 2010 the V8 project authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4 
5 #ifndef V8_V8_PROFILER_H_
6 #define V8_V8_PROFILER_H_
7 
8 #include "v8.h"
9 
10 /**
11  * Profiler support for the V8 JavaScript engine.
12  */
13 namespace v8 {
14 
15 class HeapGraphNode;
17 
18 typedef uint32_t SnapshotObjectId;
19 
20 /**
21  * CpuProfileNode represents a node in a call graph.
22  */
24  public:
25  struct LineTick {
26  /** The 1-based number of the source line where the function originates. */
27  int line;
28 
29  /** The count of samples associated with the source line. */
30  unsigned int hit_count;
31  };
32 
33  /** Returns function name (empty string for anonymous functions.) */
34  Handle<String> GetFunctionName() const;
35 
36  /** Returns id of the script where function is located. */
37  int GetScriptId() const;
38 
39  /** Returns resource name for script from where the function originates. */
40  Handle<String> GetScriptResourceName() const;
41 
42  /**
43  * Returns the number, 1-based, of the line where the function originates.
44  * kNoLineNumberInfo if no line number information is available.
45  */
46  int GetLineNumber() const;
47 
48  /**
49  * Returns 1-based number of the column where the function originates.
50  * kNoColumnNumberInfo if no column number information is available.
51  */
52  int GetColumnNumber() const;
53 
54  /**
55  * Returns the number of the function's source lines that collect the samples.
56  */
57  unsigned int GetHitLineCount() const;
58 
59  /** Returns the set of source lines that collect the samples.
60  * The caller allocates buffer and responsible for releasing it.
61  * True if all available entries are copied, otherwise false.
62  * The function copies nothing if buffer is not large enough.
63  */
64  bool GetLineTicks(LineTick* entries, unsigned int length) const;
65 
66  /** Returns bailout reason for the function
67  * if the optimization was disabled for it.
68  */
69  const char* GetBailoutReason() const;
70 
71  /**
72  * Returns the count of samples where the function was currently executing.
73  */
74  unsigned GetHitCount() const;
75 
76  /** Returns function entry UID. */
77  unsigned GetCallUid() const;
78 
79  /** Returns id of the node. The id is unique within the tree */
80  unsigned GetNodeId() const;
81 
82  /** Returns child nodes count of the node. */
83  int GetChildrenCount() const;
84 
85  /** Retrieves a child node by index. */
86  const CpuProfileNode* GetChild(int index) const;
87 
90 };
91 
92 
93 /**
94  * CpuProfile contains a CPU profile in a form of top-down call tree
95  * (from main() down to functions that do all the work).
96  */
98  public:
99  /** Returns CPU profile title. */
100  Handle<String> GetTitle() const;
101 
102  /** Returns the root node of the top down call tree. */
103  const CpuProfileNode* GetTopDownRoot() const;
104 
105  /**
106  * Returns number of samples recorded. The samples are not recorded unless
107  * |record_samples| parameter of CpuProfiler::StartCpuProfiling is true.
108  */
109  int GetSamplesCount() const;
110 
111  /**
112  * Returns profile node corresponding to the top frame the sample at
113  * the given index.
114  */
115  const CpuProfileNode* GetSample(int index) const;
116 
117  /**
118  * Returns the timestamp of the sample. The timestamp is the number of
119  * microseconds since some unspecified starting point.
120  * The point is equal to the starting point used by GetStartTime.
121  */
122  int64_t GetSampleTimestamp(int index) const;
123 
124  /**
125  * Returns time when the profile recording was started (in microseconds)
126  * since some unspecified starting point.
127  */
128  int64_t GetStartTime() const;
129 
130  /**
131  * Returns time when the profile recording was stopped (in microseconds)
132  * since some unspecified starting point.
133  * The point is equal to the starting point used by GetStartTime.
134  */
135  int64_t GetEndTime() const;
136 
137  /**
138  * Deletes the profile and removes it from CpuProfiler's list.
139  * All pointers to nodes previously returned become invalid.
140  */
141  void Delete();
142 };
143 
144 
145 /**
146  * Interface for controlling CPU profiling. Instance of the
147  * profiler can be retrieved using v8::Isolate::GetCpuProfiler.
148  */
150  public:
151  /**
152  * Changes default CPU profiler sampling interval to the specified number
153  * of microseconds. Default interval is 1000us. This method must be called
154  * when there are no profiles being recorded.
155  */
156  void SetSamplingInterval(int us);
157 
158  /**
159  * Starts collecting CPU profile. Title may be an empty string. It
160  * is allowed to have several profiles being collected at
161  * once. Attempts to start collecting several profiles with the same
162  * title are silently ignored. While collecting a profile, functions
163  * from all security contexts are included in it. The token-based
164  * filtering is only performed when querying for a profile.
165  *
166  * |record_samples| parameter controls whether individual samples should
167  * be recorded in addition to the aggregated tree.
168  */
169  void StartProfiling(Handle<String> title, bool record_samples = false);
170 
171  /** Deprecated. Use StartProfiling instead. */
172  V8_DEPRECATED("Use StartProfiling",
173  void StartCpuProfiling(Handle<String> title,
174  bool record_samples = false));
175 
176  /**
177  * Stops collecting CPU profile with a given title and returns it.
178  * If the title given is empty, finishes the last profile started.
179  */
180  CpuProfile* StopProfiling(Handle<String> title);
181 
182  /** Deprecated. Use StopProfiling instead. */
183  V8_DEPRECATED("Use StopProfiling",
184  const CpuProfile* StopCpuProfiling(Handle<String> title));
185 
186  /**
187  * Tells the profiler whether the embedder is idle.
188  */
189  void SetIdle(bool is_idle);
190 
191  private:
192  CpuProfiler();
193  ~CpuProfiler();
194  CpuProfiler(const CpuProfiler&);
195  CpuProfiler& operator=(const CpuProfiler&);
196 };
197 
198 
199 /**
200  * HeapSnapshotEdge represents a directed connection between heap
201  * graph nodes: from retainers to retained nodes.
202  */
204  public:
205  enum Type {
206  kContextVariable = 0, // A variable from a function context.
207  kElement = 1, // An element of an array.
208  kProperty = 2, // A named object property.
209  kInternal = 3, // A link that can't be accessed from JS,
210  // thus, its name isn't a real property name
211  // (e.g. parts of a ConsString).
212  kHidden = 4, // A link that is needed for proper sizes
213  // calculation, but may be hidden from user.
214  kShortcut = 5, // A link that must not be followed during
215  // sizes calculation.
216  kWeak = 6 // A weak reference (ignored by the GC).
217  };
218 
219  /** Returns edge type (see HeapGraphEdge::Type). */
220  Type GetType() const;
221 
222  /**
223  * Returns edge name. This can be a variable name, an element index, or
224  * a property name.
225  */
226  Handle<Value> GetName() const;
227 
228  /** Returns origin node. */
229  const HeapGraphNode* GetFromNode() const;
230 
231  /** Returns destination node. */
232  const HeapGraphNode* GetToNode() const;
233 };
234 
235 
236 /**
237  * HeapGraphNode represents a node in a heap graph.
238  */
240  public:
241  enum Type {
242  kHidden = 0, // Hidden node, may be filtered when shown to user.
243  kArray = 1, // An array of elements.
244  kString = 2, // A string.
245  kObject = 3, // A JS object (except for arrays and strings).
246  kCode = 4, // Compiled code.
247  kClosure = 5, // Function closure.
248  kRegExp = 6, // RegExp.
249  kHeapNumber = 7, // Number stored in the heap.
250  kNative = 8, // Native object (not from V8 heap).
251  kSynthetic = 9, // Synthetic object, usualy used for grouping
252  // snapshot items together.
253  kConsString = 10, // Concatenated string. A pair of pointers to strings.
254  kSlicedString = 11, // Sliced string. A fragment of another string.
255  kSymbol = 12 // A Symbol (ES6).
256  };
257 
258  /** Returns node type (see HeapGraphNode::Type). */
259  Type GetType() const;
260 
261  /**
262  * Returns node name. Depending on node's type this can be the name
263  * of the constructor (for objects), the name of the function (for
264  * closures), string value, or an empty string (for compiled code).
265  */
266  Handle<String> GetName() const;
267 
268  /**
269  * Returns node id. For the same heap object, the id remains the same
270  * across all snapshots.
271  */
272  SnapshotObjectId GetId() const;
273 
274  /** Returns node's own size, in bytes. */
275  V8_DEPRECATED("Use GetShallowSize instead",
276  int GetSelfSize() const);
277 
278  /** Returns node's own size, in bytes. */
279  size_t GetShallowSize() const;
280 
281  /** Returns child nodes count of the node. */
282  int GetChildrenCount() const;
283 
284  /** Retrieves a child by index. */
285  const HeapGraphEdge* GetChild(int index) const;
286 };
287 
288 
289 /**
290  * An interface for exporting data from V8, using "push" model.
291  */
292 class V8_EXPORT OutputStream { // NOLINT
293  public:
294  enum WriteResult {
296  kAbort = 1
297  };
298  virtual ~OutputStream() {}
299  /** Notify about the end of stream. */
300  virtual void EndOfStream() = 0;
301  /** Get preferred output chunk size. Called only once. */
302  virtual int GetChunkSize() { return 1024; }
303  /**
304  * Writes the next chunk of snapshot data into the stream. Writing
305  * can be stopped by returning kAbort as function result. EndOfStream
306  * will not be called in case writing was aborted.
307  */
308  virtual WriteResult WriteAsciiChunk(char* data, int size) = 0;
309  /**
310  * Writes the next chunk of heap stats data into the stream. Writing
311  * can be stopped by returning kAbort as function result. EndOfStream
312  * will not be called in case writing was aborted.
313  */
314  virtual WriteResult WriteHeapStatsChunk(HeapStatsUpdate* data, int count) {
315  return kAbort;
316  }
317 };
318 
319 
320 /**
321  * HeapSnapshots record the state of the JS heap at some moment.
322  */
324  public:
326  kJSON = 0 // See format description near 'Serialize' method.
327  };
328 
329  /** Returns heap snapshot UID (assigned by the profiler.) */
330  unsigned GetUid() const;
331 
332  /** Returns heap snapshot title. */
333  Handle<String> GetTitle() const;
334 
335  /** Returns the root node of the heap graph. */
336  const HeapGraphNode* GetRoot() const;
337 
338  /** Returns a node by its id. */
339  const HeapGraphNode* GetNodeById(SnapshotObjectId id) const;
340 
341  /** Returns total nodes count in the snapshot. */
342  int GetNodesCount() const;
343 
344  /** Returns a node by index. */
345  const HeapGraphNode* GetNode(int index) const;
346 
347  /** Returns a max seen JS object Id. */
349 
350  /**
351  * Deletes the snapshot and removes it from HeapProfiler's list.
352  * All pointers to nodes, edges and paths previously returned become
353  * invalid.
354  */
355  void Delete();
356 
357  /**
358  * Prepare a serialized representation of the snapshot. The result
359  * is written into the stream provided in chunks of specified size.
360  * The total length of the serialized snapshot is unknown in
361  * advance, it can be roughly equal to JS heap size (that means,
362  * it can be really big - tens of megabytes).
363  *
364  * For the JSON format, heap contents are represented as an object
365  * with the following structure:
366  *
367  * {
368  * snapshot: {
369  * title: "...",
370  * uid: nnn,
371  * meta: { meta-info },
372  * node_count: nnn,
373  * edge_count: nnn
374  * },
375  * nodes: [nodes array],
376  * edges: [edges array],
377  * strings: [strings array]
378  * }
379  *
380  * Nodes reference strings, other nodes, and edges by their indexes
381  * in corresponding arrays.
382  */
383  void Serialize(OutputStream* stream, SerializationFormat format) const;
384 };
385 
386 
387 /**
388  * An interface for reporting progress and controlling long-running
389  * activities.
390  */
391 class V8_EXPORT ActivityControl { // NOLINT
392  public:
395  kAbort = 1
396  };
397  virtual ~ActivityControl() {}
398  /**
399  * Notify about current progress. The activity can be stopped by
400  * returning kAbort as the callback result.
401  */
402  virtual ControlOption ReportProgressValue(int done, int total) = 0;
403 };
404 
405 
406 /**
407  * Interface for controlling heap profiling. Instance of the
408  * profiler can be retrieved using v8::Isolate::GetHeapProfiler.
409  */
411  public:
412  /**
413  * Callback function invoked for obtaining RetainedObjectInfo for
414  * the given JavaScript wrapper object. It is prohibited to enter V8
415  * while the callback is running: only getters on the handle and
416  * GetPointerFromInternalField on the objects are allowed.
417  */
418  typedef RetainedObjectInfo* (*WrapperInfoCallback)
419  (uint16_t class_id, Handle<Value> wrapper);
420 
421  /** Returns the number of snapshots taken. */
422  int GetSnapshotCount();
423 
424  /** Returns a snapshot by index. */
425  const HeapSnapshot* GetHeapSnapshot(int index);
426 
427  /**
428  * Returns SnapshotObjectId for a heap object referenced by |value| if
429  * it has been seen by the heap profiler, kUnknownObjectId otherwise.
430  */
431  SnapshotObjectId GetObjectId(Handle<Value> value);
432 
433  /**
434  * Returns heap object with given SnapshotObjectId if the object is alive,
435  * otherwise empty handle is returned.
436  */
438 
439  /**
440  * Clears internal map from SnapshotObjectId to heap object. The new objects
441  * will not be added into it unless a heap snapshot is taken or heap object
442  * tracking is kicked off.
443  */
444  void ClearObjectIds();
445 
446  /**
447  * A constant for invalid SnapshotObjectId. GetSnapshotObjectId will return
448  * it in case heap profiler cannot find id for the object passed as
449  * parameter. HeapSnapshot::GetNodeById will always return NULL for such id.
450  */
452 
453  /**
454  * Callback interface for retrieving user friendly names of global objects.
455  */
457  public:
458  /**
459  * Returns name to be used in the heap snapshot for given node. Returned
460  * string must stay alive until snapshot collection is completed.
461  */
462  virtual const char* GetName(Handle<Object> object) = 0;
463  protected:
464  virtual ~ObjectNameResolver() {}
465  };
466 
467  /**
468  * Takes a heap snapshot and returns it. Title may be an empty string.
469  */
471  Handle<String> title,
472  ActivityControl* control = NULL,
473  ObjectNameResolver* global_object_name_resolver = NULL);
474 
475  /**
476  * Starts tracking of heap objects population statistics. After calling
477  * this method, all heap objects relocations done by the garbage collector
478  * are being registered.
479  *
480  * |track_allocations| parameter controls whether stack trace of each
481  * allocation in the heap will be recorded and reported as part of
482  * HeapSnapshot.
483  */
484  void StartTrackingHeapObjects(bool track_allocations = false);
485 
486  /**
487  * Adds a new time interval entry to the aggregated statistics array. The
488  * time interval entry contains information on the current heap objects
489  * population size. The method also updates aggregated statistics and
490  * reports updates for all previous time intervals via the OutputStream
491  * object. Updates on each time interval are provided as a stream of the
492  * HeapStatsUpdate structure instances.
493  * The return value of the function is the last seen heap object Id.
494  *
495  * StartTrackingHeapObjects must be called before the first call to this
496  * method.
497  */
499 
500  /**
501  * Stops tracking of heap objects population statistics, cleans up all
502  * collected data. StartHeapObjectsTracking must be called again prior to
503  * calling PushHeapObjectsStats next time.
504  */
506 
507  /**
508  * Deletes all snapshots taken. All previously returned pointers to
509  * snapshots and their contents become invalid after this call.
510  */
511  void DeleteAllHeapSnapshots();
512 
513  /** Binds a callback to embedder's class ID. */
515  uint16_t class_id,
516  WrapperInfoCallback callback);
517 
518  /**
519  * Default value of persistent handle class ID. Must not be used to
520  * define a class. Can be used to reset a class of a persistent
521  * handle.
522  */
523  static const uint16_t kPersistentHandleNoClassId = 0;
524 
525  /** Returns memory used for profiler internal data and snapshots. */
527 
528  /**
529  * Sets a RetainedObjectInfo for an object group (see V8::SetObjectGroupId).
530  */
532 
533  private:
534  HeapProfiler();
535  ~HeapProfiler();
536  HeapProfiler(const HeapProfiler&);
537  HeapProfiler& operator=(const HeapProfiler&);
538 };
539 
540 
541 /**
542  * Interface for providing information about embedder's objects
543  * held by global handles. This information is reported in two ways:
544  *
545  * 1. When calling AddObjectGroup, an embedder may pass
546  * RetainedObjectInfo instance describing the group. To collect
547  * this information while taking a heap snapshot, V8 calls GC
548  * prologue and epilogue callbacks.
549  *
550  * 2. When a heap snapshot is collected, V8 additionally
551  * requests RetainedObjectInfos for persistent handles that
552  * were not previously reported via AddObjectGroup.
553  *
554  * Thus, if an embedder wants to provide information about native
555  * objects for heap snapshots, he can do it in a GC prologue
556  * handler, and / or by assigning wrapper class ids in the following way:
557  *
558  * 1. Bind a callback to class id by calling SetWrapperClassInfoProvider.
559  * 2. Call SetWrapperClassId on certain persistent handles.
560  *
561  * V8 takes ownership of RetainedObjectInfo instances passed to it and
562  * keeps them alive only during snapshot collection. Afterwards, they
563  * are freed by calling the Dispose class function.
564  */
565 class V8_EXPORT RetainedObjectInfo { // NOLINT
566  public:
567  /** Called by V8 when it no longer needs an instance. */
568  virtual void Dispose() = 0;
569 
570  /** Returns whether two instances are equivalent. */
571  virtual bool IsEquivalent(RetainedObjectInfo* other) = 0;
572 
573  /**
574  * Returns hash value for the instance. Equivalent instances
575  * must have the same hash value.
576  */
577  virtual intptr_t GetHash() = 0;
578 
579  /**
580  * Returns human-readable label. It must be a null-terminated UTF-8
581  * encoded string. V8 copies its contents during a call to GetLabel.
582  */
583  virtual const char* GetLabel() = 0;
584 
585  /**
586  * Returns human-readable group label. It must be a null-terminated UTF-8
587  * encoded string. V8 copies its contents during a call to GetGroupLabel.
588  * Heap snapshot generator will collect all the group names, create
589  * top level entries with these names and attach the objects to the
590  * corresponding top level group objects. There is a default
591  * implementation which is required because embedders don't have their
592  * own implementation yet.
593  */
594  virtual const char* GetGroupLabel() { return GetLabel(); }
595 
596  /**
597  * Returns element count in case if a global handle retains
598  * a subgraph by holding one of its nodes.
599  */
600  virtual intptr_t GetElementCount() { return -1; }
601 
602  /** Returns embedder's object size in bytes. */
603  virtual intptr_t GetSizeInBytes() { return -1; }
604 
605  protected:
607  virtual ~RetainedObjectInfo() {}
608 
609  private:
610  RetainedObjectInfo(const RetainedObjectInfo&);
611  RetainedObjectInfo& operator=(const RetainedObjectInfo&);
612 };
613 
614 
615 /**
616  * A struct for exporting HeapStats data from V8, using "push" model.
617  * See HeapProfiler::GetHeapStats.
618  */
620  HeapStatsUpdate(uint32_t index, uint32_t count, uint32_t size)
621  : index(index), count(count), size(size) { }
622  uint32_t index; // Index of the time interval that was changed.
623  uint32_t count; // New value of count field for the interval with this index.
624  uint32_t size; // New value of size field for the interval with this index.
625 };
626 
627 
628 } // namespace v8
629 
630 
631 #endif // V8_V8_PROFILER_H_
void DeleteAllHeapSnapshots()
const HeapGraphNode * GetFromNode() const
void StopTrackingHeapObjects()
int64_t GetSampleTimestamp(int index) const
void SetWrapperClassInfoProvider(uint16_t class_id, WrapperInfoCallback callback)
SnapshotObjectId GetObjectId(Handle< Value > value)
virtual intptr_t GetHash()=0
const HeapGraphNode * GetToNode() const
Definition: v8.h:1593
virtual ~OutputStream()
Definition: v8-profiler.h:298
SnapshotObjectId GetId() const
int64_t GetStartTime() const
virtual const char * GetName(Handle< Object > object)=0
static const int kNoColumnInfo
Definition: v8.h:1413
unsigned GetNodeId() const
Handle< String > GetScriptResourceName() const
CpuProfile * StopProfiling(Handle< String > title)
size_t GetShallowSize() const
static const int kNoLineNumberInfo
Definition: v8.h:1412
void SetSamplingInterval(int us)
const HeapGraphEdge * GetChild(int index) const
virtual ControlOption ReportProgressValue(int done, int total)=0
Handle< String > GetName() const
Handle< Value > FindObjectById(SnapshotObjectId id)
Handle< String > GetTitle() const
unsigned GetCallUid() const
int GetChildrenCount() const
virtual bool IsEquivalent(RetainedObjectInfo *other)=0
const HeapGraphNode * GetRoot() const
static const int kNoColumnNumberInfo
Definition: v8-profiler.h:89
SnapshotObjectId GetMaxSnapshotJSObjectId() const
Definition: libplatform.h:10
virtual int GetChunkSize()
Definition: v8-profiler.h:302
static const uint16_t kPersistentHandleNoClassId
Definition: v8-profiler.h:523
virtual const char * GetLabel()=0
int64_t GetEndTime() const
HeapStatsUpdate(uint32_t index, uint32_t count, uint32_t size)
Definition: v8-profiler.h:620
Type GetType() const
virtual WriteResult WriteHeapStatsChunk(HeapStatsUpdate *data, int count)
Definition: v8-profiler.h:314
const CpuProfileNode * GetChild(int index) const
virtual ~RetainedObjectInfo()
Definition: v8-profiler.h:607
size_t GetProfilerMemorySize()
Handle< Value > GetName() const
const HeapSnapshot * TakeHeapSnapshot(Handle< String > title, ActivityControl *control=NULL, ObjectNameResolver *global_object_name_resolver=NULL)
virtual ~ActivityControl()
Definition: v8-profiler.h:397
const CpuProfileNode * GetTopDownRoot() const
bool GetLineTicks(LineTick *entries, unsigned int length) const
#define V8_DEPRECATED(message, declarator)
Definition: v8config.h:338
void SetRetainedObjectInfo(UniqueId id, RetainedObjectInfo *info)
int GetScriptId() const
SnapshotObjectId GetHeapStats(OutputStream *stream)
int GetSamplesCount() const
Handle< String > GetFunctionName() const
void StartProfiling(Handle< String > title, bool record_samples=false)
virtual WriteResult WriteAsciiChunk(char *data, int size)=0
const HeapGraphNode * GetNode(int index) const
virtual void Dispose()=0
unsigned int GetHitLineCount() const
uint32_t SnapshotObjectId
Definition: v8-profiler.h:16
int GetNodesCount() const
int GetChildrenCount() const
const CpuProfileNode * GetSample(int index) const
int GetColumnNumber() const
virtual intptr_t GetElementCount()
Definition: v8-profiler.h:600
unsigned GetHitCount() const
void StartTrackingHeapObjects(bool track_allocations=false)
Type GetType() const
void SetIdle(bool is_idle)
virtual void EndOfStream()=0
unsigned GetUid() const
static const int kNoLineNumberInfo
Definition: v8-profiler.h:88
virtual intptr_t GetSizeInBytes()
Definition: v8-profiler.h:603
const HeapGraphNode * GetNodeById(SnapshotObjectId id) const
Handle< String > GetTitle() const
const HeapSnapshot * GetHeapSnapshot(int index)
#define V8_EXPORT
Definition: v8.h:57
void Serialize(OutputStream *stream, SerializationFormat format) const
const char * GetBailoutReason() const
virtual const char * GetGroupLabel()
Definition: v8-profiler.h:594
int GetLineNumber() const
static const SnapshotObjectId kUnknownObjectId
Definition: v8-profiler.h:451